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How to load a new JavaScript with AJAX and PHP
AJAX with PHP backend
So you want to load a new script the AJAX way?
This FAQ tells you how to do it with a PHP backend script. The backend script language doesn't really matter - this should give you the basic idea.
Here's what you have:
0) A server with a PHP
1) Some HTML formatted stuff
2) Some JavaScript in an external file you need to load with the HTML stuff
It takes a few files to spin it off. The flow goes like this:
A user clicks a link. This link fires a JavaScript. The JavaScript requests a specific file from a server side backend script. The backend script returns a string (or more). The return is splitted in to two parts. One part is the name of the external JavaScript to be loaded; another is the HTML formattet output to be inserted in your AJAX page.
This example assumes that the target of the HTML stuff is a DIV id'd 'contents'.
You need five files to complete this example
1) The base page
2) The JavaScript to be loaded
3) The AJAX handler
4) A server side backend to load the new content and -JavaScript
5) "The" new file - JavaScript filename reference AND HTML formatted return
So here's the code ...
1: "Base page" : [tt]index.html[/tt]
2: "JavaScript to be loaded" : [tt]new_script.js[/tt]
3: "AJAX handler" : [tt]ajax_lib.js[/tt]
4: "Server side backend" - in this example a PHP script : [tt]html_loader.php[/tt]
5: "Formatted file - Script file name & HTML stuff" : [tt]loadme.html[/tt]
Please note that in this example, the char [color red]~[/color] in the "Formatted file - Script file name & HTML stuff" is used to separate the script filename from the HTML formatted stuff. You may want or need to change the char [color red]~[/color] to something else. If you do, you need to change it i in both [tt]loadme.html[/tt] and [tt]ajax_lib.js[/tt].
Happy coding
Jak
b
This FAQ tells you how to do it with a PHP backend script. The backend script language doesn't really matter - this should give you the basic idea.
Here's what you have:
0) A server with a PHP
1) Some HTML formatted stuff
2) Some JavaScript in an external file you need to load with the HTML stuff
It takes a few files to spin it off. The flow goes like this:
A user clicks a link. This link fires a JavaScript. The JavaScript requests a specific file from a server side backend script. The backend script returns a string (or more). The return is splitted in to two parts. One part is the name of the external JavaScript to be loaded; another is the HTML formattet output to be inserted in your AJAX page.
This example assumes that the target of the HTML stuff is a DIV id'd 'contents'.
You need five files to complete this example
1) The base page
2) The JavaScript to be loaded
3) The AJAX handler
4) A server side backend to load the new content and -JavaScript
5) "The" new file - JavaScript filename reference AND HTML formatted return
So here's the code ...
1: "Base page" : [tt]index.html[/tt]
Code:
[b]<html>
<head>
<title>AJAX - loads a new script!</title>
<script type="text/javascript" src="ajax_lib.js"></script>
<style type="text/css">
#contents {
width : 500px;
height : 100px;
border : solid 1px #000;
}
</style>
</head>
<body>
<a href="javascript:send_request('loadme.html')">Try me!</a>
<hr />
<div id="contents">
</div>
</body>
</html>[/b]2: "JavaScript to be loaded" : [tt]new_script.js[/tt]
Code:
[b]function hello() {
alert('Hello world');
}[/b]3: "AJAX handler" : [tt]ajax_lib.js[/tt]
Code:
[b]function createRequestObject() {
var ro;
var browser = navigator.appName;
if(browser == "Microsoft Internet Explorer")
ro = new ActiveXObject("Microsoft.XMLHTTP");
else
ro = new XMLHttpRequest();
return ro;
}
function send_request(html_file_name) {
server_side_script = 'html_loader.php?filename=' + html_file_name;
http.open('get', server_side_script);
http.onreadystatechange = handle_response;
http.send(null);
}
var http = createRequestObject();
function handle_response() {
if(http.readyState == 4){
var response = http.responseText;
var parts = response.split('[color red]~[/color]');
if(parts.length>1) {
load_script(parts[0]);
document.getElementById('contents').innerHTML = parts[1];
} else {
document.getElementById('contents').innerHTML = response;
}
}
}
function load_script(filename) {
var script = document.createElement('script');
script.type = 'text/javascript';
script.src = filename;
document.getElementsByTagName('head')[0].appendChild(script);
}[/b]4: "Server side backend" - in this example a PHP script : [tt]html_loader.php[/tt]
Code:
[b]<?php
$file_name = $_REQUEST["filename"];
$html_file = file($file_name);
foreach($html_file as $lineno => $line)
echo $line;
?>[/b]5: "Formatted file - Script file name & HTML stuff" : [tt]loadme.html[/tt]
Code:
[b]new_script.js[color red]~[/color]<button onclick="hello()">Click me!</button>[/b]Please note that in this example, the char [color red]~[/color] in the "Formatted file - Script file name & HTML stuff" is used to separate the script filename from the HTML formatted stuff. You may want or need to change the char [color red]~[/color] to something else. If you do, you need to change it i in both [tt]loadme.html[/tt] and [tt]ajax_lib.js[/tt].
Happy coding
Jak
b