var inProgress = false;
var response = "";

	function AJAXInteraction( url, callbackMethod, xmlID, htmlID )
	{
		var req = getXmlHttpObject();
		req.onreadystatechange = processRequest;

		function getXmlHttpObject()
		{
			var xmlHttp = null;
			try
			{
				// Firefox, Opera 8.0+, Safari
				xmlHttp = new XMLHttpRequest();
			}
			catch (e)
			{
				// Internet Explorer
				try
				{
					xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
				}
				catch (e)
				{
					xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
				}
			}

			if( xmlHttp == null )
			{
				alert ( "Your browser does not support AJAX!" );
			}
			return xmlHttp;
		}

		// If the server has served the request, it should fire of the call back method
		function processRequest()
		{
			// Indicates the state or status of a request, The response is complete
			if( req.readyState == 4 )
			{
				// Indicates the apparent success of the code, if 200 no errors
				if( req.status == 200 )
				{
					if( callbackMethod )
					{	// Callback method
						callbackMethod( req, xmlID, htmlID ); // --- edited
						//alert( "success" );
						inProgress = false;
					}
				}
				else
				{
					alert( "Error orccurred = " +  req.statusText );
					inProgress = false;
				}
			}
			else // Indicates that the request is still being handled
			{
				//alert( "in progress" );
				inProgress = true;
			}
		}

	    this.doGet = function()
		{
			req.open( "GET", url, true );
			req.send( null );
		}

		this.doPost = function( body )
		{
			req.open( "POST", url, true );
			req.setRequestHeader( "Content-Type", "application/x-www-form-urlencoded" );
			req.send( body );
		}
	}

	function loadRequest( url, callbackMethod, xmlID, htmlID )
	{
		var ai = null;
		//var ai = new AJAXInteraction( url, callbackMethod, xmlID, htmlID );

		if( !inProgress ) // Not in progress
		{
			ai = new AJAXInteraction( url, callbackMethod, xmlID, htmlID );
			//ai.doGet();
			ai.doPost("var=1");
		}
		else
		{
			var shouldWait = wait( inProgress );

			if( shouldWait )
			{
				ai = new AJAXInteraction( url, callbackMethod, xmlID, htmlID );
				//ai.doGet();
				ai.doPost("var=1");
			}
		}
	}

	function wait( inProgress )
	{
		if( inProgress )
		{
			//alert( "in progress" );
			setTimeout( "wait( inProgress )", 5 );
			return true;
		}
		else
		{
			return false;
		}
	}

	function writeHTML( req, xmlID, htmlID )
	{
		document.getElementById( htmlID ).innerHTML = req.responseText;
	}

	function alertMsg( req, xmlID, htmlID )
	{
		alert( req.responseText );
	}

	function generateCombobox( req, xmlID, htmlID )
	{
		var xmlDoc = req.responseXML.documentElement;
        //alert(req.responseText);
        //alert(req.responseXML);
        //document.getElementById('showMobileModels').innerHTML = req.responseText
		var groups = req.responseXML.getElementsByTagName( xmlID ); // option
		document.getElementById( htmlID ).options.length = 0;
		document.getElementById( htmlID ).options[0] = new Option ( "Vælg", 0 );
		for( i=0; i<groups.length; i++ )
		{
			var id_element		= xmlDoc.getElementsByTagName( "id" )[i].childNodes[0];
			var value_element	= xmlDoc.getElementsByTagName( "value" )[i].childNodes[0];
			var id = 0;
			var value = null;
			if( id_element != null )
				id = id_element.nodeValue;
			if( value_element != null )
				value = value_element.nodeValue;
			document.getElementById( htmlID ).options[i+1] = new Option( value, id );
		}
		return true;
	}