读取url携带的参数

function getUrlStr(name, url) {
  const _url = url || window.location
  var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
  var r = window.location.search.substr(1).match(reg);
  if (r != null) return unescape(r[2]);
  return null;
}