Browser Calls with C# and ASP.NET MVC

Download the Code

This ASP.NET MVC web application shows how you can use the Twilio Client to make browser-to-phone and browser-to-browser calls.

Browser Calls home
page

This application powers the support site for the Birchwood Bicycle Polo Co., which sells equipment to those who play "the sport of kings." It has three main features:

  • Unsatisfied customers can submit support tickets with their phone number and their problem.
  • Support agents can call customers' phones from their browser to follow up on support tickets.
  • Customers can also use their browser to speak with support agents live when available.

In this tutorial, we'll point out the key bits of code that make this application work. Check out the project README on GitHub to see how to run the code yourself.

Learn how Zendesk uses Twilio Client to make phone support available in 40+ countries.

Submit a Support Ticket

The home page of our app displays a form for customers to submit support tickets. We use the Razor Engine to power the page.

The Ticket repository itself has just a few fields, and the Create method is just a thin wrapper for:

private readonly BrowserCallsContext _context =
    new BrowserCallsContext();

public void Create(Ticket ticket)
{
    _context.Tickets.Add(ticket);
    _context.SaveChanges();
}
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using System;
using System.Web.Mvc;
using BrowserCalls.Web.Models;
using BrowserCalls.Web.Models.Repository;

namespace BrowserCalls.Web.Controllers
{
    public class TicketsController : Controller
    {
        private readonly ITicketsRepository _repository;

        public TicketsController() : this(new TicketsRepository()) { }

        public TicketsController(ITicketsRepository repository)
        {
            _repository = repository;
        }
        public ActionResult Index()
        {
            return View(new Ticket());
        }

        public ActionResult Create(
            [Bind(Include = "Name, PhoneNumber, Description")] Ticket ticket)
        {
            ticket.CreatedAt = DateTime.UtcNow;
            if (ModelState.IsValid)
            {
                _repository.Create(ticket);
                ViewBag.Success = "Your ticket was submitted! An agent will call you soon.";
                ModelState.Clear();
                return View("Index");
            }

            return View("Index");
        }
    }
}
BrowserCalls.Web/Controllers/TicketsController.cs
Create a Ticket

BrowserCalls.Web/Controllers/TicketsController.cs

Now we can create a ticket. Next up, let's work on the dashboard for the support agent.

Make a Dashboard for our Support Agents

When a support agent visits /Dashboard, they will see all the support tickets that have been submitted.

Browser Calls support dashboard

Each ticket has also a Call Customer button which invokes a JavaScript function we wrote named callCustomer(). That function kicks off a Twilio Client call to the phone number passed, using that phone number as its sole parameter.

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@model IEnumerable<BrowserCalls.Web.Models.Ticket>

<h2>Support Tickets</h2>

<p class="lead">
    This is the list of most recent support tickets. Click the "Call customer" button to start a phone call from your browser.
</p>

<div class="row">
    <div class="col-md-4 col-md-push-8">
        <div class="panel panel-primary client-controls">
            <div class="panel-heading">
                <h3 class="panel-title">Make a call</h3>
            </div>
            <div class="panel-body">
                <p><strong>Status</strong></p>
                <div class="well well-sm" id="call-status">
                    Connecting to Twilio...
                </div>

                <button class="btn btn-lg btn-success answer-button" disabled>Answer call</button>
                <button class="btn btn-lg btn-danger hangup-button" disabled onclick="hangUp()">Hang up</button>
            </div>
        </div>
    </div>

    <div class="col-md-8 col-md-pull-4">
        @foreach (var ticket in Model)
        {
        <div class="panel panel-default">
            <div class="panel-heading">
                <h3 class="panel-title">Ticket #@ticket.Id <small class="pull-right">@ticket.CreatedAt</small></h3>
            </div>

            <div class="panel-body">

                <div class="pull-right">
                    <button onclick="callCustomer('@ticket.PhoneNumber')" type="button" class="btn btn-primary btn-lg call-customer-button">
                        <span class="glyphicon glyphicon-earphone" aria-hidden="true"></span>
                        Call customer
                    </button>
                </div>

                <p><strong>Name:</strong> @ticket.Name</p>
                <p><strong>Phone number:</strong> @ticket.PhoneNumber</p>
                <p><strong>Description:</strong></p>
                @ticket.Description
            </div>
        </div>
        }
    </div>
</div>
BrowserCalls.Web/Views/Dashboard/Index.cshtml
Support Agent's Dashboard

BrowserCalls.Web/Views/Dashboard/Index.cshtml

Great, now we have an interface good enough for our support agents. Next up, in order to let our agents make calls to their customers through the browser, we need to provide them a capability token.

Generate a Capability Token

We use the Twilio C# helper library to generate and configure our capability tokens. To allow our support agents to call the phone numbers on their tickets, we use the OutgoingClientScope.

That method requires an identifier for a TwiML Application. Twilio will send a POST request to our backend every time a user makes a Twilio Client call — the TwiML Application tells Twilio which URL to send that request to.

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using System.Collections.Generic;
using Twilio.Jwt;
using Twilio.Jwt.Client;

namespace BrowserCalls.Web.Domain.Twilio
{
    public class Capability
    {
        private readonly ICredentials _credentials;

        public Capability(ICredentials credentials)
        {
            _credentials = credentials;
        }

        public string Generate(string role)
        {
            var scopes = new HashSet<IScope>
            {
                new IncomingClientScope(role),
                new OutgoingClientScope(_credentials.TwiMLApplicationSID)
            };
            var capability = new ClientCapability(_credentials.AccountSID,
                                                  _credentials.AuthToken,
                                                  scopes: scopes);

            return capability.ToJwt();
        }
    }
}
BrowserCalls.Web/Domain/Twilio/Capability.cs
Generate a capability token

BrowserCalls.Web/Domain/Twilio/Capability.cs

Once we are equipped with our Capability Token, the next step is to set up the Twilio Device Client in the browser.

Set up a Twilio Device Client

To use the Twilio Device Client in a web browser we use the twilio.js library.

We start by retrieving a capability token from the view we defined in the previous step with a POST request through AJAX. Then we enable the Twilio Device Client for this page by passing our token to Twilio.Device.setup().

After that the Twilio.Device.ready() callback will let us know when the browser is ready to make and receive calls.

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/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
BrowserCalls.Web/Scripts/browser-calls.js
Set up a Twilio Device

BrowserCalls.Web/Scripts/browser-calls.js

Now that we have almost everything in place, it's time to see the core of this tutorial. Let's look at how we can let our agents start a call from their browsers.

Calling a Customer (browser-to-phone)

When our support agents click on the Call Customer button on a support ticket, the function highlighted on the code snippet will initiate the call.

We use Twilio.Device.connect() to begin a new outgoing call. Our backend will tell Twilio how to handle this call, so we include a phoneNumber parameter that we'll use on our Connect route.

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/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
BrowserCalls.Web/Scripts/browser-calls.js
Call a Customer

BrowserCalls.Web/Scripts/browser-calls.js

Great! Now our agents are able to make calls to their customers. Next up, let's look at how to connect that call to a phone number.

Connect the Call to a Phone Number

Whenever one of our agents starts a call, Twilio will send a POST request to the URL we set on our TwiML Application - in this case /Call/Connect.

We use TwiML to respond to the request and tell Twilio how to handle the call. Twilio will pass along the phoneNumber parameter from the previous step in its request, which we will then Dial in our TwiML.

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using System.Web.Mvc;
using BrowserCalls.Web.Domain.Twilio;
using Twilio.AspNet.Mvc;
using Twilio.TwiML;

namespace BrowserCalls.Web.Controllers
{
    public class CallController : TwilioController
    {
        private readonly ICredentials _credentials;

        public CallController() : this(new Credentials()) {}

        public CallController(ICredentials credentials)
        {
            _credentials = credentials;
        }

        // POST Call/Connect
        [HttpPost]
        public ActionResult Connect(string phoneNumber)
        {
            var response = new VoiceResponse();

            var dial = new Dial(callerId: _credentials.PhoneNumber);
            if (phoneNumber != null)
            {
                dial.Number(phoneNumber);
            }
            else
            {
                dial.Client("support_agent");
            }
            response.Dial(dial);

            return TwiML(response);
        }
    }
}
BrowserCalls.Web/Controllers/CallController.cs
Connect the call to a phone number

BrowserCalls.Web/Controllers/CallController.cs

After our Connect action method responds, Twilio completes the connection between our support agent's browser and the customer's phone. 

The call is live

We use the Twilio.Device.connect() callback to update some UI elements to notify our users that they are in a call. This function receives a Connection object, which offers some additional details about the call.

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/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
BrowserCalls.Web/Scripts/browser-calls.js
Indicate a live call

BrowserCalls.Web/Scripts/browser-calls.js

And that's all for our browser-to-phone example. Next up, we will go even further and show a browser-to-browser example.

Call a Support Agent (browser-to-browser)

Support tickets are useful, but sometimes a customer needs help right now. With just a little more work we let customers speak with a support agent live via a browser-to-browser call.

Browser Calls call support

When a customer clicks the Call support button on the home page we again use Twilio.Device.connect() to initiate the call. This time we don't pass any additional parameters — our backend will route this call to our support agent.

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/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
BrowserCalls.Web/Scripts/browser-calls.js
Call a Support Agent

BrowserCalls.Web/Scripts/browser-calls.js

Setting up the browser-to-browser call was rather simple right? Now let's look at how our backend will route this call to our support agent.

Connecting an Incoming Call from the Customer

To allow our support agents to accept incoming calls we use the IncomingClientScope class when generating their capability token, passing support_agent as the client's name:

new IncomingClientScope(role); 

When Twilio sends a POST request to our /Call/Connect URL, we can connect the call to our support agent by responding with a Client TwiML noun and the support_agent name.

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using System.Web.Mvc;
using BrowserCalls.Web.Domain.Twilio;
using Twilio.AspNet.Mvc;
using Twilio.TwiML;

namespace BrowserCalls.Web.Controllers
{
    public class CallController : TwilioController
    {
        private readonly ICredentials _credentials;

        public CallController() : this(new Credentials()) {}

        public CallController(ICredentials credentials)
        {
            _credentials = credentials;
        }

        // POST Call/Connect
        [HttpPost]
        public ActionResult Connect(string phoneNumber)
        {
            var response = new VoiceResponse();

            var dial = new Dial(callerId: _credentials.PhoneNumber);
            if (phoneNumber != null)
            {
                dial.Number(phoneNumber);
            }
            else
            {
                dial.Client("support_agent");
            }
            response.Dial(dial);

            return TwiML(response);
        }
    }
}
BrowserCalls.Web/Controllers/CallController.cs
Connect Incoming Calls

BrowserCalls.Web/Controllers/CallController.cs

That's how we prepare everything for accepting incoming calls. Now we should go back in the browser and see how to handle the connection this time.

Answer the call

When our support agent's client receives an incoming call, it will trigger the function we defined on the Twilio.Device.incoming() callback.

The incoming connection will be in a pending state until we invoke its .accept() method, which we do in a function bound to the Answer Call button.

We also set a .accept() callback to update the UI once the call is live.

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/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
BrowserCalls.Web/Scripts/browser-calls.js
Answer the call

BrowserCalls.Web/Scripts/browser-calls.js

Great! Now we know how to work on both cases: browser-to-phone and browser-to-browser calls! Next up, we will see what happens when they decide to hang up the call.

Hang up the Call

In order to finish a call we invoke Twilio.Device.disconnectAll(), which we wired to the Hang up button in our UI.

We also pass a callback function to Twilio.Device.disconnect() above, to reset some UI elements.

Loading Code Samples...
Language
/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
BrowserCalls.Web/Scripts/browser-calls.js
Hang up the Call

BrowserCalls.Web/Scripts/browser-calls.js

That's it! Our ASP.NET MVC application now powers browser-to-phone and browser-to-browser calls using Twilio Client.

Where to Next?

If you're a .NET developer working with Twilio, you might also enjoy these tutorials:

IVR: Phone Tree

Easily route callers to the right people and information with an IVR (interactive voice response) system.

Automated Survey

Instantly collect structured data from your users with a survey conducted over a voice call or SMS text messages.

Did this help?

Thanks for checking this tutorial out! If you have any feedback to share with us please contact us on Twitter, we'd love to hear it.

Agustin Camino
Jose Oliveros
Hector Ortega
David Prothero
Andrew Baker

Need some help?

We all do sometimes; code is hard. Get help now from our support team, or lean on the wisdom of the crowd browsing the Twilio tag on Stack Overflow.

1 / 1
Loading Code Samples...
using System;
using System.Web.Mvc;
using BrowserCalls.Web.Models;
using BrowserCalls.Web.Models.Repository;

namespace BrowserCalls.Web.Controllers
{
    public class TicketsController : Controller
    {
        private readonly ITicketsRepository _repository;

        public TicketsController() : this(new TicketsRepository()) { }

        public TicketsController(ITicketsRepository repository)
        {
            _repository = repository;
        }
        public ActionResult Index()
        {
            return View(new Ticket());
        }

        public ActionResult Create(
            [Bind(Include = "Name, PhoneNumber, Description")] Ticket ticket)
        {
            ticket.CreatedAt = DateTime.UtcNow;
            if (ModelState.IsValid)
            {
                _repository.Create(ticket);
                ViewBag.Success = "Your ticket was submitted! An agent will call you soon.";
                ModelState.Clear();
                return View("Index");
            }

            return View("Index");
        }
    }
}
@model IEnumerable<BrowserCalls.Web.Models.Ticket>

<h2>Support Tickets</h2>

<p class="lead">
    This is the list of most recent support tickets. Click the "Call customer" button to start a phone call from your browser.
</p>

<div class="row">
    <div class="col-md-4 col-md-push-8">
        <div class="panel panel-primary client-controls">
            <div class="panel-heading">
                <h3 class="panel-title">Make a call</h3>
            </div>
            <div class="panel-body">
                <p><strong>Status</strong></p>
                <div class="well well-sm" id="call-status">
                    Connecting to Twilio...
                </div>

                <button class="btn btn-lg btn-success answer-button" disabled>Answer call</button>
                <button class="btn btn-lg btn-danger hangup-button" disabled onclick="hangUp()">Hang up</button>
            </div>
        </div>
    </div>

    <div class="col-md-8 col-md-pull-4">
        @foreach (var ticket in Model)
        {
        <div class="panel panel-default">
            <div class="panel-heading">
                <h3 class="panel-title">Ticket #@ticket.Id <small class="pull-right">@ticket.CreatedAt</small></h3>
            </div>

            <div class="panel-body">

                <div class="pull-right">
                    <button onclick="callCustomer('@ticket.PhoneNumber')" type="button" class="btn btn-primary btn-lg call-customer-button">
                        <span class="glyphicon glyphicon-earphone" aria-hidden="true"></span>
                        Call customer
                    </button>
                </div>

                <p><strong>Name:</strong> @ticket.Name</p>
                <p><strong>Phone number:</strong> @ticket.PhoneNumber</p>
                <p><strong>Description:</strong></p>
                @ticket.Description
            </div>
        </div>
        }
    </div>
</div>
using System.Collections.Generic;
using Twilio.Jwt;
using Twilio.Jwt.Client;

namespace BrowserCalls.Web.Domain.Twilio
{
    public class Capability
    {
        private readonly ICredentials _credentials;

        public Capability(ICredentials credentials)
        {
            _credentials = credentials;
        }

        public string Generate(string role)
        {
            var scopes = new HashSet<IScope>
            {
                new IncomingClientScope(role),
                new OutgoingClientScope(_credentials.TwiMLApplicationSID)
            };
            var capability = new ClientCapability(_credentials.AccountSID,
                                                  _credentials.AuthToken,
                                                  scopes: scopes);

            return capability.ToJwt();
        }
    }
}
/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
using System.Web.Mvc;
using BrowserCalls.Web.Domain.Twilio;
using Twilio.AspNet.Mvc;
using Twilio.TwiML;

namespace BrowserCalls.Web.Controllers
{
    public class CallController : TwilioController
    {
        private readonly ICredentials _credentials;

        public CallController() : this(new Credentials()) {}

        public CallController(ICredentials credentials)
        {
            _credentials = credentials;
        }

        // POST Call/Connect
        [HttpPost]
        public ActionResult Connect(string phoneNumber)
        {
            var response = new VoiceResponse();

            var dial = new Dial(callerId: _credentials.PhoneNumber);
            if (phoneNumber != null)
            {
                dial.Number(phoneNumber);
            }
            else
            {
                dial.Client("support_agent");
            }
            response.Dial(dial);

            return TwiML(response);
        }
    }
}
/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
using System.Web.Mvc;
using BrowserCalls.Web.Domain.Twilio;
using Twilio.AspNet.Mvc;
using Twilio.TwiML;

namespace BrowserCalls.Web.Controllers
{
    public class CallController : TwilioController
    {
        private readonly ICredentials _credentials;

        public CallController() : this(new Credentials()) {}

        public CallController(ICredentials credentials)
        {
            _credentials = credentials;
        }

        // POST Call/Connect
        [HttpPost]
        public ActionResult Connect(string phoneNumber)
        {
            var response = new VoiceResponse();

            var dial = new Dial(callerId: _credentials.PhoneNumber);
            if (phoneNumber != null)
            {
                dial.Number(phoneNumber);
            }
            else
            {
                dial.Client("support_agent");
            }
            response.Dial(dial);

            return TwiML(response);
        }
    }
}
/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}
/**
 * Twilio Client configuration for the browser-calls-csharp
 * example application.
 */

// Store some selectors for elements we'll reuse
var callStatus = $("#call-status");
var answerButton = $(".answer-button");
var callSupportButton = $(".call-support-button");
var hangUpButton = $(".hangup-button");
var callCustomerButtons = $(".call-customer-button");

/* Helper function to update the call status bar */
function updateCallStatus(status) {
    callStatus.text(status);
}

/* Get a Twilio Client token with an AJAX request */
$(document).ready(function () {
    $.post("/Token/Generate", { page: window.location.pathname }, function (data) {
        // Set up the Twilio Client Device with the token
        Twilio.Device.setup(data.token);
    });
});

/* Callback to let us know Twilio Client is ready */
Twilio.Device.ready(function (device) {
    updateCallStatus("Ready");
});

/* Report any errors to the call status display */
Twilio.Device.error(function (error) {
    updateCallStatus("ERROR: " + error.message);
});

/* Callback for when Twilio Client initiates a new connection */
Twilio.Device.connect(function (connection) {
    // Enable the hang up button and disable the call buttons
    hangUpButton.prop("disabled", false);
    callCustomerButtons.prop("disabled", true);
    callSupportButton.prop("disabled", true);
    answerButton.prop("disabled", true);

    // If phoneNumber is part of the connection, this is a call from a
    // support agent to a customer's phone
    if ("phoneNumber" in connection.message) {
        updateCallStatus("In call with " + connection.message.phoneNumber);
    } else {
        // This is a call from a website user to a support agent
        updateCallStatus("In call with support");
    }
});

/* Callback for when a call ends */
Twilio.Device.disconnect(function (connection) {
    // Disable the hangup button and enable the call buttons
    hangUpButton.prop("disabled", true);
    callCustomerButtons.prop("disabled", false);
    callSupportButton.prop("disabled", false);

    updateCallStatus("Ready");
});

/* Callback for when Twilio Client receives a new incoming call */
Twilio.Device.incoming(function (connection) {
    updateCallStatus("Incoming support call");

    // Set a callback to be executed when the connection is accepted
    connection.accept(function () {
        updateCallStatus("In call with customer");
    });

    // Set a callback on the answer button and enable it
    answerButton.click(function () {
        connection.accept();
    });
    answerButton.prop("disabled", false);
});

/* Call a customer from a support ticket */
function callCustomer(phoneNumber) {
    updateCallStatus("Calling " + phoneNumber + "...");

    var params = { "phoneNumber": phoneNumber };
    Twilio.Device.connect(params);
}

/* Call the support_agent from the home page */
function callSupport() {
    updateCallStatus("Calling support...");

    // Our backend will assume that no params means a call to support_agent
    Twilio.Device.connect();
}

/* End a call */
function hangUp() {
    Twilio.Device.disconnectAll();
}