// Script 13.2 - ajax.js
/* This page creates an Ajax request object.
* This page is included by other pages that
* need to perform an XMLHttpRequest. */
// Initialize the object:
var ajax = false;

// Create the object...

// Choose object type based upon what's supported:
if (window.XMLHttpRequest) {

 // IE 7, Mozilla, Safari, Firefox, Opera, most browsers:
ajax = new XMLHttpRequest();

} else if (window.ActiveXObject) { //Older IE browsers

 // Create type Msxml2.XMLHTTP, if possible:
try {
ajax = new
ActiveXObject("Msxml2.XMLHTTP");
} catch (e1) { // Create the older type instead:
try {
ajax = new
ActiveXObject("Microsoft.XMLHTTP");
} catch (e2) { }
}

}

 // Send an alert if the object wasn't created.
 if (!ajax) {
 alert ('Some page functionality is unavailable.');
 }