1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Insert title here</title> 6 <script type="text/javascript"> 7 //ajax引擎对象 8 var xmlHttpRequest=null; 9 try { 10 xmlHttpRequest=new ActiveXObject("Msxml2.XMLHTTP"); 11 } catch (e) { 12 //alert("非IE浏览器"); 13 try { 14 15 xmlHttpRequest = new XMLHttpRequest(); 16 } catch (e) { 17 xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP"); 18 } 19 20 } 21 22 23 function checkUserName(t){ 24 var userName=t.value; 25 var reqUrl="data.do?userName="+userName; 26 //监听第二步 绑定ajax引擎的监听对象 27 var passwd="passwd="+userName; 28 29 30 alert("test"); 31 xmlHttpRequest.onreadystatechange=function(){ 32 alert(xmlHttpRequest.readyState); 33 if(xmlHttpRequest.readyState==4 && xmlHttpRequest.status==200){ 34 //alert(xmlHttpRequest.responseText); 35 } 36 } 37 //3，绑定提交地址open(method,url,isAsynchronous) 38 xmlHttpRequest.open("post",reqUrl,true); 39 40 //如果使用POST请求发送数据，需要设置请求头 41 xmlHttpRequest.setRequestHeader('Content-typ','application/x-www-form-urlencoded'); 42 43 //4,发送请求 44 xmlHttpRequest.send(passwd); 45 } 46 </script> 47 </head> 48 <body> 49 用户名<input type="text" id="userName" onchange="checkUserName(this)" > 50 密码<input type="password" id="passwd" onchange="checkUserName(this)" > 51 </body> 52 </html>