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

jQuery Essential Training

Using AJAX helpers


From:

jQuery Essential Training

with Joe Marini

Video: Using AJAX helpers

In addition to the basic AJAX function, jQuery provides a set of shorthand helper methods that help cover some common scenarios that arise when using AJAX with jQuery, and we're going to take a look at a couple of those now. So here in the jQuery API documentation, I'm going to click in the AJAX section on the Shorthand Methods. You can see there is a small set of these. The get function loads data from the server using an HTTP get request, and that's sort of like using the AJAX function with the type property of get, only this is a shorter more convenient way of doing that.
Expand all | Collapse all
  1. 2m 52s
    1. Welcome
      1m 9s
    2. Using the exercise files
      1m 43s
  2. 17m 37s
    1. What is jQuery?
      5m 19s
    2. Downloading and installing jQuery
      2m 20s
    3. Creating a simple jQuery-enabled page
      7m 12s
    4. Overview of jQuery's features
      2m 46s
  3. 59m 57s
    1. Overview of selectors and filters
      2m 9s
    2. Using basic jQuery selectors
      9m 6s
    3. Using basic jQuery filters
      8m 35s
    4. Using jQuery attribute filters
      6m 7s
    5. Child, visibility, and content filters
      9m 59s
    6. Form selectors and filters
      9m 3s
    7. Traversing documents
      9m 1s
    8. Understanding jQuery statement chaining
      1m 42s
    9. Practical example 1: Annotating page links
      4m 15s
  4. 47m 16s
    1. Creating, getting, and setting content
      5m 53s
    2. Manipulating attributes
      5m 43s
    3. Inserting content
      4m 57s
    4. Wrapping, replacing, and removing content
      5m 27s
    5. Working with CSS
      6m 19s
    6. Associating data with page elements
      9m 30s
    7. Practical example 2: Automatic TOC generator
      9m 27s
  5. 33m 6s
    1. Understanding the jQuery event handling features
      2m 4s
    2. Binding and unbinding events
      6m 23s
    3. Convenient event helper methods
      4m 40s
    4. Using the jQuery event object
      6m 21s
    5. Using miscellaneous event features
      4m 38s
    6. Practical example 3: Table striping and highlighting
      9m 0s
  6. 28m 45s
    1. Hiding and showing elements
      5m 23s
    2. Fading elements in and out
      4m 2s
    3. Sliding elements
      4m 3s
    4. Creating custom animations
      5m 58s
    5. Practical example 4: Image rotator
      9m 19s
  7. 25m 30s
    1. Introduction to jQuery UI
      3m 40s
    2. Exploring the jQuery UI widgets
      5m 24s
    3. Exploring the jQuery UI effects
      3m 58s
    4. Using the jQuery UI ThemeRoller
      4m 11s
    5. Downloading and installing jQuery UI
      8m 17s
  8. 47m 49s
    1. Overview of the sample web site
      3m 50s
    2. Using the accordion widget
      9m 14s
    3. Creating an image rotator
      10m 22s
    4. Building hover tooltips
      7m 26s
    5. Making an image selector
      9m 30s
    6. Using the Resizable effect
      7m 27s
  9. 30m 2s
    1. Working with Asynchronous JavaScript and XML (AJAX)
      10m 8s
    2. Using AJAX helpers
      4m 34s
    3. Understanding AJAX data types
      10m 14s
    4. Using global AJAX event handlers
      5m 6s
  10. 20s
    1. Goodbye
      20s

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...
jQuery Essential Training
4h 53m Beginner Sep 01, 2009 Updated May 24, 2013

Viewers: in countries Watching now:

In jQuery Essential Training, Microsoft professional Joe Marini presents the power of the jQuery library, an open-source JavaScript project that greatly simplifies the process of adding advanced functionality to web sites. Joe teaches how to use these new features to build pages that work across browsers with the functionality that today's users (and clients) are looking for, from complex animation effects to dynamic page formatting. Joe pulls all of this together, showing how the jQuery UI plug-in can expand and streamline the capability of jQuery, and then integrating jQuery design tools into a complete sample web site. Exercise files accompany the course.

Topics include:
  • Constructing jQuery selectors and filters to gather information from web pages
  • Creating, inserting, and manipulating web page content
  • Understanding jQuery statement chaining
  • Building event handlers that work across browsers
  • Working with jQuery effects, such as showing, hiding, and fading page elements
  • Creating custom animations with specialized properties and options
  • Using the jQuery UI plug-in to give pages a polished look
Subjects:
Developer Mobile Apps Web Mobile Web Web Development
Software:
Ajax jQuery jQuery Mobile
Author:
Joe Marini

Using AJAX helpers

In addition to the basic AJAX function, jQuery provides a set of shorthand helper methods that help cover some common scenarios that arise when using AJAX with jQuery, and we're going to take a look at a couple of those now. So here in the jQuery API documentation, I'm going to click in the AJAX section on the Shorthand Methods. You can see there is a small set of these. The get function loads data from the server using an HTTP get request, and that's sort of like using the AJAX function with the type property of get, only this is a shorter more convenient way of doing that.

The get function has a couple of specialized counterparts. There is getJSON for getting JSON data from the server, and then there is the getScript version, which loads a JavaScript file and then executes it. There is the post function, which is again, kind of like using the basic AJAX function, with a post option, but this is a more shorthand way of doing it. Then there is the load function, which loads data from the server and takes the content that comes back and puts it into the matched element. And so we are going to take a look at using the get function and the load function in this movie.

So let's take a look at the get function. The get function takes a URL and it takes any data that you want to send to the server--so these could be you know URL- encoded properties that would normally be sent on the query string. And then there's a function to call and case things are successful, and then there is an optional dataType. Now if you don't provide a dataType, the jQuery library will just simply try to make an intelligent guess as to what kind of data you're looking to come back, either XML JSON, text, whatever. This is a pretty simple function to use.

Let's go back over to our code and take a look at an example of using it. So here in Aptana Studio, I've got my Helpers_start document open, and it looks pretty similar to the one that we used in the previous movie for the AJAX function. Here, on my document ready function, I have a function called getData, and getData is what we're going to fill out. Now, last time when we did this-- remember we did $.ajax and that's not we're going to be doing this time. This time we are going to be using the get function.

And to do that I am simply going to write $.get, or of course I could have written you know jQuery.get, but dollar sign is more convenient. So I write $.get, and I am going to get the same text file, so it's going to be testdata.txt. And then I need to give the name of the success function and that's this function right here, successFn. When successFn is called, the result will be the data that came back from the server, and then we're going to get a reference to our content paragraph, which is right here and put the result inside of it.

Okay, so we're going to save this, and then once again, using Aptana Studio, I am going to run this using my local web server. And you can do this however you want to. You can post this to whatever server you use it for testing or whatever IDE you happen to be using. But I am going to run this using my local server here in Aptana, so I'll bring it up in Chrome, and you can see that what's happening is the result is coming back from the server and being placed into the paragraph. All right, so let's go back to the code. Now, it turns out that this combination right here of getting data and then using the successFn to put the result into an element on the page is so common that jQuery actually gives you a shorthand way just of doing that, and so let's go back up here to get data and comment this out.

What we're going to do this time is simply, on the element itself, dollar sign and we're going to get the content paragraph, we're going to call the load function. And the load function will actually go out and kick off an AJAX request, and we're going to ask for testdata.txt. Now, that's all that we need to do. So this right here, load, is going to go out to the server, look for this URL, take the result, and put it into whatever element matches this selector right here.

So we are going to save, and just to be sure that we're not somehow triggering the successFn, let's go ahead and comment that out. So we'll save and we'll run this again using the internal server, and you can see that it worked. So we refresh, and you can see that the text data is coming back from the server and being put into the element on the page all with one line of code. So if you have a need to use AJAX that fits one of these comment scenarios then the jQuery AJAX helper functions can make your job a lot easier.

Find answers to the most frequently asked questions about jQuery Essential Training.


Expand all | Collapse all
Please wait...
Q: When attempting to download jQuery, as the author does in the movie “Downloading and installing jQuery,” the file does not download. When any of the links on the download page are clicked, the browser opens a page of code instead.
A: This sometimes happens when a web browser doesn't have the proper MIME type to prompt the user to download the file instead of open it directly. Therefore, the browser is opening the code instead of downloading it. If this occurs, download the file on a by Control-clicking (Mac) or right-clicking (Windows) on the download link and choosing the Save File option, which will download it to the computer.
Q: Why do some of the examples use the form $("document") instead of just $(document)?
A: jQuery's $(document).ready() function will work with either form. As a reminder, you can also just use the $() shorthand to accomplish the same thing:
 
$(function() {
// code to run when the document is ready
});
Q: I am stuck on the first exercise in Chapter 1, video 3 "Creating a simple jQuery enabled page".

Your example javascript code, both in the movie and in the exercise files,
reads as follows:

<script type="text/javascript">
$("document").ready(function() {
alert("The page just loaded!");
});
</script>

This is not working for me.
A: After jQuery 1.3.2, a change was made where quotes were no
longer needed around the "document" argument to the jQuery $() function.

Type the following instead.

<script type="text/javascript">
$(document).ready(function() {
alert("The page just loaded!");
});
</script>
Q: How do I remove the resize handle that appears on on <textarea> elements in some browsers, such as Firefox and Chrome?
A: Some browsers automatically provide this feature for these text elements. You can disable this feature using CSS by providing a style rule for the element that specifies no resize behavior. Add the rule "resize: none;" to a stylesheet that is applied to the textarea, and the resize handle will not appear.

Q: This course was updated on 5/24/2013. What changed?

A: This update includes a new chapter on the jQuery AJAX features, new movies on associating data with page elements, and updates to the chapters on events and the jQuery UI plugin to reflect changes in JQuery 1.8.
Q: In Chapter 7, for the "Using the Resizable effect" movie, the example code from the Groundswell_Final and Groundswell_Start folders isn't limiting the width of the window. What should I do?
A: There's a bug in the example file. You need to add: 
textarea { resize:none;}

to the main.css file in the _css folder, and change the link tag in register.htm from:

<link href="../_css/sunny/jquery-ui-1.7.2.custom.css" rel="stylesheet" type="text/css" media="screen, projection" />

to

<link href="../_css/sunny/jquery-ui-1.10.2.custom.css" rel="stylesheet" type="text/css" media="screen, projection" />

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 jQuery Essential Training.

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