Basic Client Side Steps for AJAX

1. Create and XMLHttpRequestObject

This requires a very slight amount of multi-browser scripting...

I found this example at http://ajaxpatterns.org/XMLHttpRequest_Call

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function createXMLHttpRequest() {
try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) {}
try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) {}
try { return new XMLHttpRequest(); } catch(e) {}
alert("XMLHttpRequest not supported");
return null;
}
var xhReq = createXMLHttpRequest();
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2. Execute the open method of the object

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xhReq.open("GET", "showmelove.html", true);
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3. Assign a method to be called when the object is ready

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function iAmBack(){
alert("The server called back")
}
xhReq.onreadystatechange = iAmBack;
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4. Execute the send method

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xhReq.send(null);
##################################################

Try it out by copying the following two files and putting them on some server that you can access with a web browser... You can even put them in a local directory and access them via your web browser, but you will need to click "Allow Blocked Content" in your browser
#################PUTTING IT ALL TOGETHOR FILE 1##################
NOTE: name this file - index.html
<script language="javascript">

function createXMLHttpRequest() {
try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) {}
try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) {}
try { return new XMLHttpRequest(); } catch(e) {}
alert("XMLHttpRequest not supported");
return null;
}

var xhReq = createXMLHttpRequest(); <!--- Here's where we create the object -->

function iAmBack(){ <!-- Here is the method that is called when we're done -->
if (xhReq.readyState != 4) { return; }
var serverResponse = xhReq.responseText;
alert(serverResponse) <!-- Here is where we shout out what we got from the server >
}

function showMeSomeServerLove(){ <!--- Here's where all of the magic happens -->
xhReq.open("GET", "showmelove.html", true);
xhReq.onreadystatechange = iAmBack;
xhReq.send(null);
}

<a onclick="showMeSomeServerLove()">Click For Love</a>

How do I love thee? Let me count the ways.
I love thee to the depth and breadth and height
My soul can reach, when feeling out of sight
For the ends of Being and ideal Grace.
I love thee to the level of everyday's
Most quiet need, by sun and candle-light.
I love thee freely, as men strive for Right;
I love thee purely, as they turn from Praise.
I love thee with the passion put to use
In my old griefs, and with my childhood's faith.
I love thee with a love I seemed to lose
With my lost saints!---I love thee with the breath,
Smiles, tears, of all my life!---and, if God choose,
I shall but love thee better after death.
-- Elizabeth Barrett Browning