iframe获取父级域名

不跨域：parent.location或top.location

跨域：document.referrer

function getParentUrl() { 
  var url = null;
  if (parent !== window) {
    try {
      url = parent.location.href; 
        }
    catch (e) {
      url = document.referrer; 
     } 
   }
  return url; 
}

参考：https://www.shangmayuan.com/a/bc07af30a9a04224a6ec4cdb.html