<script type="text/javascript">
function IsExist(url)
{
x = new ActiveXObject("Microsoft.XMLHTTP")
x.open("HEAD",url,false)
x.send()
return x.status==200
}
alert(IsExist("http://www.survivalescaperooms.com/logos.gif"))
</script>

<SCRIPT language="javascript">
var xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
xmlhttp.Open("GET", "http://www.survivalescaperooms.com/logos.gif", false);
xmlhttp.Send();
alert(xmlhttp.responseText);
</SCRIPT>

<img src="http://www.survivalescaperooms.com/logos2.gif" onerror="alert('該圖片不存在!');">