W3School TIY
编辑您的代码：
<html> <head> <script type="text/javascript"> function showHint(str) { var xmlhttp; if (str.length==0) { document.getElementById("txtHint").innerHTML=""; return; } 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("txtHint").innerHTML=xmlhttp.responseText; } } xmlhttp.open("GET","/ajax/gethint.asp?q="+str,true); xmlhttp.send(); } </script> </head> <body> <h3>请在下面的输入框中键入字母（A - Z）：</h3> <form action=""> 姓氏：<input type="text" id="txt1" onkeyup="showHint(this.value)" /> </form> <p>建议：<span id="txtHint"></span></p> </body> </html>
查看结果: