?function getUrlParam(name) {
 
  var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
  var r = window.location.search.substr(1).match(reg);
  if (r != null) return unescape(r[2]);
  return null;
}
 
function wxLogin(callback) {
  var appId = 'xxxxxxxxxxxxxxxxxxx';
  var oauth_url = encodeURIComponent（window.location.href.split('#')[0]）;
  var url = "https://open.weixin.qq.com/connect/oauth2/authorize?appid=" + appId + "&redirect_uri=" + oauth_url  + "&response_type=code&scope=snsapi_base&state=STATE#wechat_redirect"
  var code = getUrlParam("code");
  if (!code) {
    window.location = url;
  } else {
    $.ajax({
      type: 'GET',
      url: oauth_url,
      dataType: 'json',
      data: {
        code: code
      },
      success: function (data) {
        if (data.code === 200) {
          callback(data.data)
        }
      },
      error: function (error) {
        throw new Error(error)
      }
    })
  }