JavaScript基于Ajax实现不刷新在网页上动态显示文件内容

!DOCTYPE html>
html>
head>
title>sharejs.com/title>
script>
function loadXMLDoc()
{
var xmlhttp;
if (window.XMLHttpRequest)
 {// code for IE7+, Firefox, Chrome, Opera, Safari
 xmlhttp=new XMLHttpRequest();
 }
else
 {// code for IE6, IE5
 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
 }
xmlhttp.onreadystatechange=function()
 {
 if (xmlhttp.readyState==4  xmlhttp.status==200)
  {
  document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
  }
 }
xmlhttp.open("GET","ajax_info.txt",true);
xmlhttp.send();
}
/script>
/head>
body>
div id="myDiv">h2>Let AJAX change this text/h2>/div>
button type="button" onclick="loadXMLDoc()">Change Content/button>
/body>
/html>