<img
  src="http://www.example.com/no-such-page"
  onload="alert(':)')"
  onerror="alert(':(')"
>

var xmlHttp
function comrat(id, str)
{
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
 {
 alert ("Browser does not support HTTP Request")
 return
 }
var url="comrat.php"
url=url+"?q="+str
url=url+"&id="+id

xmlHttp.onreadystatechange=stateChangedcom(id)
xmlHttp.open("GET",url,true)
xmlHttp.send(null)
}
function stateChangedcom(id)
{
if(xmlHttp.readyState==0)
	{
 document.getElementById("model-"+id).innerHTML="<img src=images/load3.gif width=5 height=5>";
	}
if(xmlHttp.readyState==1)
	{
 document.getElementById("model-"+id).innerHTML="<img src=images/load23.gif width=5 height=5>";
	}
	if(xmlHttp.readyState==2)
	{
 document.getElementById("model-"+id).innerHTML="<img src=images/load3.gif width=5 height=5>";
	}
		if(xmlHttp.readyState==3)
	{
 document.getElementById("model-"+id).innerHTML="<img src=images/load3.gif width=5 height=5>";
	}
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
 {
 document.getElementById("model-"+id).innerHTML=xmlHttp.responseText
 }
}

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;
}