代码示例:(标识:xmle_xmlhttprequest_js3)
<html>
<head>
<script type="text/javascript">
var xmlhttp
function loadXMLDoc(url)
{
xmlhttp=null
// code for Mozilla, etc.
if (window.XMLHttpRequest)
{
xmlhttp=new XMLHttpRequest()
}
// code for IE
else if (window.ActiveXObject)
{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP")
}
if (xmlhttp!=null)
{
xmlhttp.onreadystatechange=state_Change
xmlhttp.open("GET",url,true)
xmlhttp.send(null)
}
else
{
alert("Your browser does not support XMLHTTP.")
}
}
function state_Change()
{
// if xmlhttp shows "loaded"
if (xmlhttp.readyState==4)
{
// if "OK"
if (xmlhttp.status==200)
{
document.getElementById('T1').innerHTML="This file was last modified on: " + xmlhttp.getResponseHeader('Last-Modified')
}
else
{
alert("Problem retrieving data:" + xmlhttp.statusText)
}
}
}
</script>
</head>
<body onload="loadXMLDoc('/static/demo/txt/xmle_test_xmlhttp.txt')">
<p>
With a HEAD request, a server will return the headers of a resource (not the resource itself). This means you can find out the Content-Type or Last-Modified of a document, without downloading it itself.
</p>
<div id="T1" style="border:1px solid black;width:300"></div>
</body>
</html>