// JavaScript Document

	var xmlHttp;
	var itemsPreview;
	var indexPreview;

	function getXMLData(url,stateFunction){ 
	
	  try{
		  //alert('getXMLData');
		xmlHttp=GetXmlHttpObject();
		
		if (xmlHttp==null){
 			alert ("Your browser does not support this script!");
			return;
		}

		xmlHttp.onreadystatechange=stateFunction;
		xmlHttp.open("GET",url,true);
		xmlHttp.send(null);
		
	  }catch(ee){		   
		  // document.write('<h1>HTTP 404 - File not found</h1>' + '\n' + ee.description);	
	  }
	}
	
	function PreloadStateChanged(){
		
	  try{
		if (xmlHttp.readyState==4){
				xmlString = xmlHttp.responseText.toString();
			
				var xmlobject ;	
				try{
					xmlobject = (new DOMParser()).parseFromString(xmlString, "text/xml");
				}catch(ee){
					try{
						xmlobject=new ActiveXObject("Microsoft.XMLDOM");
						xmlobject.async="false";
						xmlobject.loadXML(xmlString);						
					}catch(excep){
						alert('Unable to load : ' + excep.message);
					}
				}
				
				/*alert(xmlString);*/
				
				var root = xmlobject.getElementsByTagName('Root')[0];	
				itemsPreview = root.getElementsByTagName("Img");		
				for ( var i=0; (i< itemsPreview.length) && (i<3); i++){
					document.images['img' + (i+1).toString() ].src = itemsPreview[i].getElementsByTagName("Path")[0].firstChild.nodeValue;					
						
				}		
				
				indexPreview = i-1;				
		}
			
	  	}catch(ee){
			 // alert('Err : ' + ee.description);
		}
	}


	
	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");
			}
  		}		
		return xmlHttp;
	}
	
	this.onload=function(){	
	
			getXMLData('images/xImg/preImg.xml',PreloadStateChanged);		
				
	}
	

	function btnNextGroup(){
		
		try{
			
			if( indexPreview > itemsPreview.length-2)
				return;		
			indexPreview ++;				
			document.images['img1'].src = document.images['img2'].src;
			document.images['img2'].src = document.images['img3'].src;
			document.images['img3'].src = itemsPreview[indexPreview].getElementsByTagName("Path")[0].firstChild.nodeValue;
						
		}catch(excep){
			alert(excep.message);
		}
		
		return false;
	}
	
	function btnPrevGroup(){
		
		try{
						
			if( indexPreview < 3)
				return;
			indexPreview --;				
			
			document.images['img3'].src = document.images['img2'].src;
			document.images['img2'].src = document.images['img1'].src;
			document.images['img1'].src = itemsPreview[indexPreview-2].getElementsByTagName("Path")[0].firstChild.nodeValue;
			
		}catch(excep){
			alert(excep.description);
		}
		
		return false;
	}