​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>XMLHttpRequest 对象</h1>
​
<h2>请在下面的输入字段中键入字母 A-Z：</h2>
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<p>搜索建议：<span id="txtHint"></span></p> 
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<p>姓名：<input type="text" id="txt1" onkeyup="showHint(this.value)"></p>
​
<script>
function showHint(str) {
  var xhttp;
  if (str.length == 0) { 
    document.getElementById("txtHint").innerHTML = "";
    return;
  }
  xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("txtHint").innerHTML = this.responseText;
    }
  };
  xhttp.open("GET", "/demo/gethint.php?q="+str, true);
  xhttp.send();   
}
</script>
​
</body>
</html>
​