https://open.weixin.qq.com/connect/oauth2/authorize?appid=wxa70527e1ffa01384&redirect_uri=http%3a%2f%2fm.yuanxd.com%3a8091%2fweixinoa%2fmobile%2fwdgl%2fwendangguanli.html&response_type=code&scope=snsapi_base&state=a#wechat_redirect XMLHTTPRequest对象的说明DEMO