利用js操作cookie记录评论者信息

从来没正经看过js的知识，所以虽然简单，在实现过程中却费了不少劲。
setcookie.js
function $(m,n){
return document.forms[m].elements[n].value;
}

function rememberMe () {
//在点击发表评论是触发该函数，将相应的值传递给addCookie()
var cookie_email = $("comments_form","email");
var cookie_name = $("comments_form","author");
var cookie_expireHours = 900;
addCookie("name",cookie_name,cookie_expireHours);
addCookie("email",cookie_email,cookie_expireHours);
}
function addCookie(objName,objValue,objHours){//添加cookie
var str = objName + "=" + escape(objValue);
var date = new Date();
var ms = objHours*3600*1000;
date.setTime(date.getTime() + ms);
str += "; expires=" + date.toGMTString();
document.cookie = str;
}
//读取cookie，并将对应值显示在文本框里
var arrStr = document.cookie.split("; ");
for(var i = 0;i < arrStr.length;i ++){
var temp = arrStr.split("=");
if(temp[0] == "name") document.comments_form.author.value=temp[1];
if(temp[0] == "email") document.comments_form.email.value=temp[1];
}