案例：ajax案例     状态：可编辑再运行    进入竖版
 运行结果　
​x
 
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<html>
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<head>
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<script type="text/javascript">
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function showHint(str)
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{
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var xmlhttp;
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if (str.length==0)
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  {
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  document.getElementById("txtHint").innerHTML="";
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  return;
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  }
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if (window.XMLHttpRequest)
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  {// code for IE7+, Firefox, Chrome, Opera, Safari
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  xmlhttp=new XMLHttpRequest();
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  }
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else
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  {// code for IE6, IE5
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  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
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  }
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xmlhttp.onreadystatechange=function()
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  {
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  if (xmlhttp.readyState==4 && xmlhttp.status==200)
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    {
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    document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
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    }
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  }
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xmlhttp.open("GET","/example/aspnet/gethint.aspx?q="+str,true);
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xmlhttp.send();
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}
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</script>
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</head>
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<body>
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​
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<h3>请在下面的输入框中键入字母（A - Z）：</h3>
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<form action="">
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姓氏：<input type="text" id="txt1" onkeyup="showHint(this.value)" />
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</form>
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<p>建议：<span id="txtHint"></span></p>
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​
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</body>
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</html>