​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>XMLHttpRequest 对象</h1>
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<button type="button" onclick="loadDoc()">请求数据</button>
​
<p>单击该按钮几次以查看时间是否已更改，或文件是否已缓存。</p>
​
<p id="demo"></p>
​
<script>
function loadDoc() {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange=function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("demo").innerHTML = this.responseText;
    }
  };
  xhttp.open("GET", "/demo/demo_get.asp?t=" + Math.random(), true);
  xhttp.send();
}
</script>
​
</body>
</html>
​