读取url地址里参数的值

如何从页面url地址里获取参数的值,并指定参数值进行判定操作
如地址 http://www.example.com/?channel=qd1&app=weixin

<script>
  //查询地址里的参数
  var getQueryValue = function (key, href) {
    href = href || window.location.search;
    var match = href.match(new RegExp('[?&]' + key + '=([^&]*)'));
    return match && match[1] && decodeURIComponent(match[1]) || '';
  };

  //获取channel的值
  var channel = getQueryValue('channel');
  var app = getQueryValue('app');
  console.log(channel);
  console.log(app);

  //按channel值进行判断处理
  if (channel == "qd1") {
    $('.box1').show();
  } else if (channel == "qd2" || channel == "qd3") {
    $('.box3').show();
  } else {
    $('.box4').show();
  };
</script>