Review: delivering the Prototype JavaScript library without compressing its source files - AJAX

Google's Ajax Libraries API is a programming interface that permits web developers to download popular JavaScript packages, such as Prototype, jQuery and Scriptaculous, directly from Google’s servers instead of using local copies of these libraries. In this fourth part of a four-part series on using the API, you'll learn how to serve the jQuery framework without compression.

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By: Alejandro Gervasio

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January 26, 2009

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I will start my explanation of how to serve the jQuery package via the Google API without using compression by reintroducing a hands-on example created in the previous article. It showed the same process with the Prototype library.

The example in the last article illustrated how to build a basic Ajax application that was capable of reading the content of a text file in the server, and theny displaying it on the browser. As I said before, these tasks were performed by means of Prototype, whose source files were served uncompressed.

That being said, here’s how this Ajax application looked originally:

(definition for 'ajax_file_reader.htm' file)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<head>

<title>Reading file contents with Prototype library (uses Google API)</title>

body{

padding: 0;

margin: 0;

background: #fff;

}

h1{

font: bold 18pt Arial, Helvetica, sans-serif;

color: #000;

}

#filecontents{

width: 600px;

padding: 10px;

border: 1px solid #999;

font: normal 10pt Arial, Helvetica, sans-serif;

color: #000;

}

</style>

// load Prototype library with Google API (loads uncompressed source file)

google.load("prototype", "1.4",{uncompressed:true});

// read file contents with Ajax

function readFileContents(){

// send http request

var ajaxobj=new Ajax.Request('read_file.php',{method: 'get',onComplete: displayFileContents,onFailure: displayError});

}

// display file contents

function displayFileContents(requestObj){

$('filecontents').innerHTML=requestObj.responseText;

}

// display error message

function displayError(requestObj){

$('filecontents').innerHTML='Error reading file contents!';

}

// initialize file reading application

function initializeApplication(){

// attach click handler to HTML button

Event.observe('btn','click',readFileContents);

}

google.setOnLoadCallback(initializeApplication);

</script>

</head>

<body>

<h1>Reading File Contents with Prototype library (uses Google API)</h1>

</body>

</html>

definition for 'read_file.php' file)

<?php

if(!$contents=file_get_contents('data.txt')){

trigger_error('Error reading file contents',E_USER_ERROR);

}

echo $contents;

(definition for 'data.txt' file)

These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file. These are contents of sample file.

Certainly, I’m not going to spend additional time explaining how the previous Ajax program actually works, since this was covered in depth in preceding tutorials of the series. I would like to remind you, however, of the way the “google.load()” method was instructed to download the Prototype library without using compression.

You'll understand this process better if you look at the following line of code:

google.load("prototype", "1.4",{uncompressed:true});

Now that you hopefully recalled how to use the Google API for delivering the Prototype package in an uncompressed manner, it’s time to see how this process can be recreated using the jQuery library.

To learn the full details of how this will be achieved, please click on the link below and keep reading.

Next: Serving the jQuery library without using compression >>