How to replace url parameters with JS regular expression

/* 定义替换对象键值 */
var setReferArgs = function(){
 var referArgs = new Object();
 referArgs['#userID\#'] = userId;
 referArgs['\#userName\#'] = userName;
 return referArgs;
}
/* 替换URL的参数 */
var replaceUrlParams = function(url){
 var actualUrl = "";
 var referArgs = setReferArgs();
 for(var key in referArgs){
 var e = eval('/'+ key +'/g'); 
 actualUrl = url.replace(e,referArgs[key]);
 url = actualUrl;
 }
 return actualUrl;
}

//从url中获取参数值
 function getvl(name) {
 var reg = new RegExp("(^|\\?|&)"+ name +"=([^&]*)(\\s|&|$)", "i");
 if (reg.test(location.href)) return unescape(RegExp.$2.replace(/\+/g, " "));
 return "";
 };
 var code = getvl("code");