通过设置Access-Control-Allow-Origin来实现跨域访问比较简单。
例如：客户端的域名是www.client.com,而请求的域名是www.server.com
如果直接使用ajax访问，会有以下错误
XMLHttpRequest cannot load http://www.server.com/server.php. No 'Access-Control-Allow-Origin' header is present on the requested resource.Origin 'http://www.client.com' is therefore not allowed access.
在被请求的Response header中加入
// 指定允许其他域名访问 header('Access-Control-Allow-Origin:*'); // 响应类型 header('Access-Control-Allow-Methods:POST'); // 响应头设置 header('Access-Control-Allow-Headers:x-requested-with,content-type');
就可以实现ajax POST跨域访问了。
代码如下：
client.html 路径：http://www.client.com/client.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <meta http-equiv="content-type" content="text/html;charset=utf-8"> <title> 跨域测试 </title> <script src="//code.jquery.com/jquery-1.11.3.min.js"></script> </head> <body> <div id="show"></div> <script type="text/javascript"> $.post("http://www.server.com/server.php",{name:"fdipzone",gender:"male"}) .done(function(data){ document.getElementById("show").innerHTML = data.name + ' ' + data.gender; }); </script> </body> </html>
server.php 路径：http://www.server.com/server.php
<?php $ret = array( 'name' => isset($_POST['name'])? $_POST['name'] : '', 'gender' => isset($_POST['gender'])? $_POST['gender'] : '' ); header('content-type:application:json;charset=utf8'); header('Access-Control-Allow-Origin:*'); header('Access-Control-Allow-Methods:POST'); header('Access-Control-Allow-Headers:x-requested-with,content-type'); echo json_encode($ret); ?>
Access-Control-Allow-Origin:* 表示允许任何域名跨域访问
如果需要指定某域名才允许跨域访问，只需把Access-Control-Allow-Origin:*改为Access-Control-Allow-Origin:允许的域名
例如：header('Access-Control-Allow-Origin:http://www.client.com');
如果需要设置多个域名允许访问，这里需要用php处理一下
例如允许 www.client.com 与 www.client2.com 可以跨域访问
server.php 修改为
<?php $ret = array( 'name' => isset($_POST['name'])? $_POST['name'] : '', 'gender' => isset($_POST['gender'])? $_POST['gender'] : '' ); header('content-type:application:json;charset=utf8'); //$_SERVER['HTTP_ORIGIN']访问者的域名 $origin = isset($_SERVER['HTTP_ORIGIN'])? $_SERVER['HTTP_ORIGIN'] : ''; $allow_origin = array( 'http://www.client.com', 'http://www.client2.com' ); if(in_array($origin, $allow_origin)){ header('Access-Control-Allow-Origin:'.$origin); header('Access-Control-Allow-Methods:POST'); header('Access-Control-Allow-Headers:x-requested-with,content-type'); } echo json_encode($ret); ?>