ajax+php实现无刷新验证手机号的实例

!DOCTYPE html>
html>
head>
meta charset="utf-8">
style>
#btn{width:80px;height:30px;}
/style>
/head>
body>
form> 
请输入手机号：
input type="text" id="name" name="name">
input type="button" onclick="show()" id="btn" value="验证">
/form>
p id="txt">/p>
script>
var usernamereg = /^1(3|4|5|7|8)\d{9}$/;
function show(){	
var name=document.getElementById("name").value;
var xmlHttp=new XMLHttpRequest();
var url="post.php";
xmlHttp.onreadystatechange=function stateChanged() 
{ 
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){ 
 	if(!usernamereg.test(name)){
 		document.getElementById("txt").innerHTML="手机号有误";
	}else{
 	document.getElementById("txt").innerHTML=xmlHttp.responseText 
 		} 
 	}
}
xmlHttp.open("POST",url,true);
xmlHttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xmlHttp.send("name=" + name);
} 
/script>
/body>
/html>

?php
$con = mysqli_connect('localhost', 'username', 'password');
if(! $con )
{
 die('连接失败: ' . mysqli_error($con));
}
mysqli_select_db($con,'bdm256727651_db');
$username = "select userName FROM Forms where userName = '$_POST[name]' ";
$result = mysqli_query($con,$username );
$rows=mysqli_num_rows($result);
if($rows){
	echo "手机号已注册"	;
	exit;
}else{
	echo "手机号可用";	
}
mysqli_close($con)
?>