function getXMLHTTP() { //fuction to return the xml http object
	var xmlhttp=false;	
	try{
		xmlhttp=new XMLHttpRequest();
	}
	catch(e) {		
		try{			
			xmlhttp= new ActiveXObject("Microsoft.XMLHTTP");
		}
		catch(e){
			try{
			req = new ActiveXObject("Msxml2.XMLHTTP");
			}
			catch(e1){
				xmlhttp=false;
			}
		}
	}
		
	return xmlhttp;
}


function changeDisplay(divId,imgId) {	
	showLrgImg(divId,imgId);
}

function showLrgImg(divId,imgId) {
	var strURL="includes/display-image.php?id="+imgId;
	var req = getXMLHTTP();
	
	if (req) {		
		req.onreadystatechange = function() {
			if (req.readyState == 4) {
				// only if "OK"
				if (req.status == 200) {						
					document.getElementById('display-large_'+divId).innerHTML=req.responseText;			
				} else {
					alert("There was a problem while using XMLHTTP:\n" + req.statusText);
				}
			}				
		}			
		req.open("GET", strURL, true);
		req.send(null);
	}	
}