JavaScript获取地址栏url参数

function params() {
  const search = window.location.search;
  search = search.substr(1, search.length);
  const res = {};
  if (!search) return res;
  search.split('&').map(item => {
    const [key, value] = item.split('=');
    res[key] = decodeURIComponent(value);
  });
  return res;
}