/*
 * This function creates an XMLHttpRequest object
 * and stores it in a global variable called request.
 * This method tries to create the object different ways
 * to support Mozilla-based and IE browsers
 */
function createXMLHttpRequest()
{
	request = null;

	if ( window.XMLHttpRequest ) // Mozilla-Based Browsers
		{       
			request = new XMLHttpRequest();
		}
	else if ( window.ActiveXObject )// newer IE browsers
		{  
			request = new ActiveXObject( "Msxml2.XMLHTTP" );
			if ( request == null )// older IE Browsers
				{           
					request = new ActiveXObject( "Microsoft.XMLHTTP" );
				}
		}

	//The request could still be null
	if ( request == null )
		{
			alert( "Your browser does not support AJAX" );
		}
}

/*
 * This function will send the URL passed in as an AJAX call
 * using the HTTP GET method.
 */
function sendHttpGetRequest( theURL )
{
	//alert("Sending GET to "+theURL);
	request.open( 'GET', theURL, true );
	request.onreadystatechange = handleHttpResponse;
	request.send(null);
}

/*
 * This function will send the URL passed in as an AJAX call
 * using the HTTP POST method.
 * The postData variable should contain all the name=value
 * pairs to be sent to theURL.
 */
function sendHttpPostRequest( theURL, postData )
{
	//alert("Sending POST to "+ theURL);
	request.onreadystatechange = handleHttpResponse;
	request.open( 'POST', theURL, true );
	request.setRequestHeader( "Content-Type","application/x-www-form-urlencoded; charset=UTF-8" );
	request.send( postData );
}

/*
 * This method is called by the browser when the AJAX response is
 * received from the server
 */
function handleHttpResponse()
{
	//alert("handle response, ready state = "+request.readyState);
	if ( request.readyState == 4 ) // ReadyState of 4 means finished
		{     
			if ( request.status == 200 ) // HTTP status of 200 means ALL OK
				{    
					// Get the response as plain text
					ajaxResultText = request.responseText;
			
					// Call displayResults. This method must be implemented
					// for each page to do the page specific logic.
					displayResults( ajaxResultText );
				}
			else
				{
					alert( "An error occurred: " +request.status + ":" +request.statusText );
				}
		}
}