跨域获取

本地：

<?php
    $_arr = array('a'=>1,'b'=>2,'c'=>3);
    $_result = json_encode($_arr);
    echo $_result;
?>

    //本地获取
    $('form input[type=button]').click(function(){
        $.ajax({
            type:"post",
            url:"test.php",
            async:true,
            dataType:'json',
            success:function(response,status,xhr){
                alert(response.a);
            }
        });
    });

跨域获取：假如在www.dang.cc上有一个test2.php文件如下

<?php
    $_arr = array('a'=>1,'b'=>2,'c'=>3);
    $_result = json_encode($_arr);
    $_callback = $_GET['callback'];
    echo $_callback."($_result)";
?>

    //远程获取
    $('form input[type=button]').click(function(){
        $.ajax({
            type:"post",
            url:"http://www.dang.cc/test2.php",
            async:true,
            dataType:'jsonp',
            success:function(response,status,xhr){
                alert(response.a);
            }
        });
    });