$(oFind).bind('click',function(){
        var oKeyword = $('.locating').val();
        if( oKeyword != '' ){
            $.ajax({
                type:"post",
                async:true,
                url: "{:U('Reply/index')}",
                data:{keyword:oKeyword},
                success:function(){
                    $(oZs).fadeOut("fast");
                    $(oCx).fadeIn("fast");
                }
            });
        }
    });

oFind是个按钮，给他绑定一个点击事件以后，向后台发送ajax请求，查看控制台一切正常，所带参数，url均无错误，

<?php
namespace Home\Controller;
use Think\Controller;

class ReplyController extends CommonController {
    public function index(){
        if($_POST){
            
            echo "ddd";

        }
　
    　}
}

但是　就是打印不出ddd? 帮俺看看哪有错？