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JavaScript and AJAX

Preparing a live search AJAX app


From:

JavaScript and AJAX

with Ray Villalobos

Video: Preparing a live search AJAX app

So it's time get busy with a real project in AJAX. I'm going to show you how to build a live search application, and this is what the application looks like when it's done. This application lets you type in some text in this input field and shows you only the records in the JSON document that match the search. It's dynamic, in that it updates as you're typing them. We're going to use some of what we have learned about AJAX so far and use some of jQuery's power to handle the heavy lifting. So let me go over the documents I'm going to start with. First off, I've cleared up the JavaScript file so that it has nothing in it.

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JavaScript and AJAX
1h 12m Intermediate Jan 18, 2013

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The ability to read data and communicate information asynchronously is fundamental to modern web applications. In this course, author Ray Villalobos takes a look at integrating AJAX (Asynchronous JavaScript and XML) with JavaScript and jQuery—a combination that makes it easy to work with dynamic data and reduces the number of requests to the server. The course first explains what AJAX is, and shows how to load and reload pages with pure JavaScript, update the DOM, and read and parse data in the XML and JSON formats. Next, learn how to read and write information between the server and the client with AJAX methods in jQuery, and build a dynamic search application that updates search results as you type.

Topics include:
  • What is AJAX?
  • Making requests asynchronous
  • Updating the DOM with getElementById
  • Reading JSON files
  • Working with jQuery and AJAX
  • Sending and searching JSON data
  • Incorporating CSS transitions
Subjects:
Developer Web Programming Languages Web Development
Software:
Ajax JavaScript
Author:
Ray Villalobos

Preparing a live search AJAX app

So it's time get busy with a real project in AJAX. I'm going to show you how to build a live search application, and this is what the application looks like when it's done. This application lets you type in some text in this input field and shows you only the records in the JSON document that match the search. It's dynamic, in that it updates as you're typing them. We're going to use some of what we have learned about AJAX so far and use some of jQuery's power to handle the heavy lifting. So let me go over the documents I'm going to start with. First off, I've cleared up the JavaScript file so that it has nothing in it.

I want to begin with a clean slate. I'm going to get rid of some of the files I no longer need that are still in my server like this data.xml and this data.txt file. So I'm hitting Command+Delete, I'm in Transmit, and then hit this Delete button, gets rid of them. Eventually I'll need to add a style sheet to my HTML file, so I'll go ahead and right-click in Transmit and select New File and type in mystyle.css. You may have also noticed that I uploaded a folder full of images, and these are just photos of the different speakers.

So the HTML that I'm starting with is pretty simple. I've changed the title to Live Search, and I just have div with an ID of update and a link to the jQuery and the script.js documents. So the first thing I'm going to need is to add a section for my search area. So I'll create a div, the id will be searcharea, and in here I'll type in an input field. I'll make it of type search. In some browsers you may see the edges have rounded corners. Now, it doesn't really matters what I type for name because this is not going to be part of a normal form, but I do have to add an ID value here because that's what we're going to target JavaScript.

I don't need a value, so I'll take that out. I am going to add a placeholder. That's an HTML 5 feature that let's you put in something that the reader can see before they type anything. So if I switch over here and I clear my search, you can see that it says name or info right there, so that's what I'm going to type here: name or info. So this going to need a label. A label is just the text that goes with the input field, and it has an advantage of making the label clickable to the input field. So this needs to match the id, so I'll do an id of search here, and my label is just going to say livesearch.

That means that when I am here, if I click on the word livesearch, because that's the label, it will activate my field. That is something really useful for mobile devices. And I'll add a little paragraph here to just describe what the user is supposed to do. So, let me save that. Finally, I need to add a link to my style sheet. And the style is called mystyle.css.

I don't need a type here. Let me save that. One thing I like to do is to just put a simple rule in the style sheet to make sure that it's linking properly to the HTML file. So I'll add a body selector here, background, and just give it a background color. So let me save this and I'll switch back to my browser. I need to go to a slightly different URL here. And everything looks like it's working great. So we've done a little bit of work here, and this is pretty much it for our HTML file and our folder structure.

It's a really simple page, so now we can move on to start scripting the document.

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