​x
 
<!DOCTYPE html>
<html>
<body>
​
<div id="demo">
<h1>XMLHttpRequest 对象</h1>
<button type="button" onclick="loadDoc()">修改内容</button>
</div>
​
<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/js/ajax_info.txt", true);
  xhttp.send();
}
</script>
​
</body>
</html>
​