1.新建 a.html 
复制代码 代码如下: 
<!doctype html> 
<html> 
<head> 
<meta charset='utf-8'> 
<title>iframe式ajax调用</title> 
</head> 
<body> 
<form action='b.php' method='post' name='' id='' target='formTarget'> 
<input type='text' name='username' id='' placeholder='' value='' /> 
<input type='submit' name='' value='提交' /> 
<span id='msg'></span> 
</form> 
<iframe src='' name='formTarget' id='formTarget' style='display:none'></iframe> 
</body> 
</html>  
2.新建 b.php 
复制代码 代码如下: 
<?php 
echo " 
<script> 
parent.document.getElementById('msg').innerHTML = 'iframe式ajax调用成功!'; 
alert('您输入的是:{$_POST['username']}'); 
window.setTimeout(function(){ 
parent.window.location.reload(); 
},3000); 
</script> 
";  
3.访问: http://localhost/a.html 
效果如图