两个不同域名的程序在处理ajax的时候肯定会有跨域的存在，一种方式是通过jsonp，一种是通过请求本域名，然后后端PHP转发curl，还有一种比较简单 通过header头来实现，例如
现在有两个域名 www.host1.com 和 www.host2.com 在host1.com下面请求host2.com下面的Php文件。
例如 http://www.host1.com/index.html中这样写
<!DOCTYPE HTML> <html lang="en-US"><head> <meta charset="UTF-8"> <title></title> <script src="http://cdn.bootcss.com/jquery/2.2.4/jquery.js"></script> </head> <body> <script type="text/javascript"> $(function(){ $.post("http://www.host2.com/test.php",{"name":"lizhaoyao","sex":"man"},function(res){ console.log(res); },"json"); }); </script> </body> </html>
一个很简单的ajax请求，传送 name 和sex 给 http://www.host2.com/test.php 该文件这样写
<?php $ret = array( 'name' => isset($_POST['name'])? $_POST['name'] : '', 'sex' => isset($_POST['sex'])? $_POST['sex'] : '' ); echo json_encode($ret); ?>
然后通常情况下会出现一个跨域提醒
XMLHttpRequest cannot load http://www.host2.com/test.php. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost' is therefore not allowed access. The response had HTTP status code 404.
然后我们可以加一段代码
$origin = isset($_SERVER['HTTP_ORIGIN'])? $_SERVER['HTTP_ORIGIN'] : '';
header('content-type:application:json;charset=utf8');
header('Access-Control-Allow-Origin:'.$origin);
header('Access-Control-Allow-Methods:POST');
header('Access-Control-Allow-Headers:x-requested-with,content-type');
如图：
<?php $ret = array( 'name' => isset($_POST['name'])? $_POST['name'] : '', 'sex' => isset($_POST['sex'])? $_POST['sex'] : '' ); $origin = isset($_SERVER['HTTP_ORIGIN'])? $_SERVER['HTTP_ORIGIN'] : ''; header('content-type:application:json;charset=utf8'); header('Access-Control-Allow-Origin:'.$origin); header('Access-Control-Allow-Methods:POST'); header('Access-Control-Allow-Headers:x-requested-with,content-type'); echo json_encode($ret); exit();
再看效果
xhr请求成功！