php跨域表单请求实现，只要在公共继承类库加入header头部处理代码

header('Access-Control-Allow-Origin:*');
header('Access-Control-Allow-Methods:POST');

header('Access-Control-Allow-Headers:x-requested-with,content-type');

例如：

//以下代码实在Thinkphp框架下实现的，公共自动加载方法
public function _initialize(){
    header('Access-Control-Allow-Origin:*');
    header('Access-Control-Allow-Methods:POST');
    header('Access-Control-Allow-Headers:x-requested-with,content-type');
}