/*注册用户名检查小例子*/
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
.box{
margin:100px auto;
text-align:center;}
</style>
</head>
<body>
<div class="box">
姓名:<input type="text" id="userName"/>
密码:<input type="password" id="pass"/>
<input type="button" value="注册" id="btn"/>
</div>
<script>
//http://本机IP/AJAX/checkname regname:要验证的用户名 注册时，即时验证用户名是否存在
var userName = document.getElementById("userName");
var pass = document.getElementById("pass");
var oBtn = document.getElementById("btn");
userName.onblur = function(){
var request;
if(window.XMLHttpRequest){
request = new window.XMLHttpRequest;
}else{
request = new ActiveXObject("MSxml12.XMLHTTP");
}
request.open("get","http://localhost?AJAX/checkname?regname"+"="+userName.value,true);
request.readystatechange = function(){
if(request.readyState == 4){
if(request.status == 200){
if(request.responseText = "yes"){
alert("用户名存在!不可用");
}else{
alert("可用");
}
}
}
}
request.send(null);
}
</script>
</body>
</html>