用JS获得地址栏上的参数值

Javascript代码

String.prototype.getQueryString = function(name)
{
  var reg = new RegExp("(^|&|\\?)"+ name +"=([^&]*)(&|$)"), r;
  if ( r=this.match(reg) ) return unescape(r[2]);
  return null;
}
       var httpUrl = document.URI;
       var userName_f1 =  httpUrl.getQueryString("user");