Start learning with our library of video tutorials taught by experts. Get started

HTML5: Messaging and Communications in Depth
Watching:

An interactive example


From:

HTML5: Messaging and Communications in Depth

with Bill Weinman

Video: An interactive example

Now let's take a look at a more interactive example of cross-origin messaging. This is a little chat app, and while it may not be terribly useful to chat between two windows on a single desktop, it does give us an opportunity to explore some of the subtleties of the messaging interface. So this application works much like the ones that we've seen so far; in fact it uses a lot of the same code. The first thing that it does is it loads up the second window inside a frame, and then the second window inside a frame sends a message back to the first window to tell it that it's loaded.

Watch this entire course now—plus get access to every course in the library. Each course includes high-quality videos taught by expert instructors.

Become a member
Please wait...
HTML5: Messaging and Communications in Depth
43m 19s Intermediate Jan 23, 2012

Viewers: in countries Watching now:

This course shows how to communicate between web pages, both within a single domain and across one or more domains, using the HTML5 Messaging API. Author Bill Weinman reviews security and the same origin policy, details cross-origin scripting techniques, and explores examples of cross-document messaging. The course describes how to register and send messages to listeners and handle errors.

Subjects:
Developer Web Web Development
Software:
HTML
Author:
Bill Weinman

An interactive example

Now let's take a look at a more interactive example of cross-origin messaging. This is a little chat app, and while it may not be terribly useful to chat between two windows on a single desktop, it does give us an opportunity to explore some of the subtleties of the messaging interface. So this application works much like the ones that we've seen so far; in fact it uses a lot of the same code. The first thing that it does is it loads up the second window inside a frame, and then the second window inside a frame sends a message back to the first window to tell it that it's loaded.

So you'll see in the first window, which is the outer one, we have this log "this is windowOne" and its host, one.3sn.net. And windowTwo is on two.3sn.net so they are in different origins. And then once windowTwo gets loaded, it sends this message to windowOne that says, "windowTwo is loaded." And the purpose of that is so that windowOne now has a handle to windowTwo's window object or rather, a window proxy object that works just like its window object. You'll also notice that it says info, and the reason for that is that we're actually sending some structured data that categorizes the different types of messages.

And we have two different types of messages: we have info message and we have chat messages. So when I come up here and I type a message, a chat message, you'll see that that message shows up over here without saying info in front of it. And if I send one over here, you see that it comes up over here without it saying info in front of it. And the reason for that is that there are actually two different categories of messages that are being sent, and it's being sent as structured data with JSON.

And the reason we're using JSON is because this application worked just fine with the structured data except on the Internet Explorer. And in order to for it to work on Internet Explorer, we had to use JSON, because Internet Explorer is only sending strings in its data payload. So now that we've seen how the app works, in the next movie we'll take a look at the code and see how it's implemented.

There are currently no FAQs about HTML5: Messaging and Communications in Depth.

Share a link to this course
Please wait... Please wait...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.
Upgrade now


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Upgrade now

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed HTML5: Messaging and Communications in Depth.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Welcome to the redesigned course page.

We’ve moved some things around, and now you can



Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked