//app.js

App({

  onLaunch: function() {

    wx.login({

      success: function(res) {

        if (res.code) {

          //发起网络请求

          wx.request({

            url: 'https://test.com/onLogin',

            data: {

              code: res.code

            }

          })

        } else {

          console.log('获取用户登录态失败！' + res.errMsg)

        }

      }

    });

  }

})

//获取用户openid

function getopenid(){

    $js_code = I('post.code');

    if(empty($js_code)) return array('status'=>0,'info'=>'缺少js_code');

    $appid = 'xxxxxxxxxxxxx';

    $appsecret = 'xxxxxxxxxxxxxxxxxxxxxx';

    $curl = 'https://api.weixin.qq.com/sns/jscode2session?appid=%s&secret=%s&js_code=%s&grant_type=authorization_code';

    $curl = sprintf($curl,$appid,$appsecret,$js_code);

    $result = request($curl);

    return array('status'=>1,'info'=>json_decode($result,true));

}

//正常返回的JSON数据包

{

      "openid": "OPENID",

      "session_key": "SESSIONKEY",

      "unionid": "UNIONID"

}

//错误时返回JSON数据包(示例为Code无效)

{

    "errcode": 40029,

    "errmsg": "invalid code"

}