function createRequestObject()
{
	var ro;
  var browser = navigator.appName;

  if(browser == "Microsoft Internet Explorer") {
		// on IE, we have to use ActiveX
  	ro = new ActiveXObject("Microsoft.XMLHTTP");
  } else {
  	// on every other browser, we can directly create a new XMLHttpRequest object
    ro = new XMLHttpRequest();
  }
  return ro;
}

var http = createRequestObject();

// ajax image preloader
function changeprevimg(whichdiv, whicharea, whichimage, imagewidth)
{
  document.getElementById(whichdiv).innerHTML = '';
  http.open("get", "http://www.portman-motors.com/scripts/ajax_image_loader.asp?area="+whicharea+"&image="+whichimage+"&width="+imagewidth);
  http.onreadystatechange = function ()
{	
	if(http.readyState == 1){
	// loading
	document.getElementById(whichdiv).innerHTML = "<img src=\"/images/image_loading.gif\" alt=\"Loading\" />";
	}
	if((http.readyState == 4) && (http.status == 200)){
	  var response = http.responseText;
	  document.getElementById(whichdiv).innerHTML = response;
  }
}
  http.send(null);
}