A Newbie Tutorial to AJAX

Here is a simple tutorial for AJAX aspirants who just want to know how ajax works wihout digging into server side programming.

Needed Tools:

• Text Editor (preferably Notepad++)

• IE 6+, Firefox 0.8+.

Needed Files:

• A html file (named as ajax.html)

• A text file (named as sample.txt)

Make the html file named anything.

• I hav named it "ajax.html"

<html>

<head>
​

<title>
​

A Simple Ajax Example
​

</title>
​

<script type="text/javascript">
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<!-- Older browser hidden soce
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function doAjax(fileToRead){
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var request = null;
​

var str;
​

if(window.XMLHttpRequest)
​

{
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str = "inside XMLHttpRequest"
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document.getElementById("displayDiv").innerHTML= str;
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request = new XMLHttpRequest();
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}
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else if(window.ActiveXObjexct)
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{
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str = "inside ActiveXObject"
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document.getElementById("displayDiv").innerHTML= str;
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request = new ActiveXObject("Miscrosoft.XMLHTTP");
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}


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if (request)
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{
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request.open("GET",fileToRead);
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request.onreadystatechange = function()
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{
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if(request.readyState == 4)
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{
​

str = str + " <br> yahoo ajax xompleted" + "<br> content of file sample.txt is:<br>" + request.responseText;
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document.getElementById("displayDiv").innerHTML=str;
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}
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}
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request.send(null);
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}
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else
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{
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alert("you must upgrade your browser!");
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}
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}
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-->
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</script>
​

</head>

<body>
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<input type="button" value="make ajax request" onClick="doAjax('sample.txt');return true;">
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<div id="displayDiv"></div>
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</body>
​

</html>

Click to expand...

Now make another file "sample.txt" from where the data will be fetched to html page.
Let the content be anything u want.

• Here are mine "sample.txt" contents:

u got the ajax request completed
with the data from this file named
sample.txt

Click to expand...

Working:

• open "ajax.html" in browser

• when u click on "make a ajax request" button the content of file "sample.txt" will be fetched without a reload of webpage.

• thats it.

Explaination:
Will provide an in-detail explaination soon as am havin exams now