微信网页授权原理分析
https://open.weixin.qq.com/connect/oauth2/authorize?appid=APPID&redirect_uri=http://www.xxx.com.cn/kyz/test.php&response_type=code&scope=snsapi_base&state=STATE#wechat_redirect
微信中打开这个地址会跳转到
http://www.xxx.com.cn/kyz/test.php?code=081RqiGa1cxz8A