1，ajax分为$.ajax()，$.get()，$.post()，$.getJSON() 几种形式，实例如下：
<html><meta http-equiv="Content-Type" content="text/html;charset=utf-8"><script type="application/javascript" src="../js/jquery-1.7.2.js"></script><script type="application/javascript">$(document).ready(function(){ $("#ajaxBut").click(function(){ $.ajax({ 'type':'get', 'url':'test4.php', 'dateType':'json', 'data':$("input").serialize(), 'success':function(ret){ alert(ret); } }); }); $("#getBut").click(function(){ $.get("test4.php",$("input").serialize(),function(ret){ alert(ret); }); }); $("#postBut").click(function(){ $.post("test5.php",$("input").serialize(),function(ret){ alert(ret); }); }); $("#jsonBut").click(function(){ $.getJSON("test4.php",$("input").serialize(),function(ret){ alert(ret); }); }); });</script><body><form> <h1>user Login</h1> username:<input type="text" name="user" id="user" /><br/> password:<input type="password" name="password" id="password"/><br/> <input type="button" name="but" id = "ajaxBut" value="ajaxLogin" /> <input type="button" name="but" id = "postBut" value="postLogin" /> <input type="button" name="but" id = "getBut" value="getLogin" /> <input type="button" name="but" id = "jsonBut" value="jsonLogin" /></form></body></html>
<?php$username = $_GET['user'];$password = $_GET['password'];$ret = "fail";if($username == 'zhangsan' && $password == '123'){ $ret = "success";}echo json_encode($ret);
<?php$username = $_POST['user'];$password = $_POST['password'];$ret = "fail";if($username == 'zhangsan' && $password == '123'){ $ret = "success";}echo json_encode($ret);
2，ajax跨域获取数据，使用到jsonp，实例如下：
$.getJSON("http://www.ganji.com/test6.php?callback=?", $("input").serialize() , function(data){ if(data){ console.log(data); }});
$str = 'OK';$callback = $_GET('callback'); if (!empty($callback)) { header("content-type: application/x-javascript; charset=UTF-8"); echo $callback . '(' . $str . ')'; } else { echo $str; }}
