js操作cookies

function setCookie(name,value)
{
    var Days = 30;
    var exp  = new Date();    //new Date("December 31, 9998");
        exp.setTime(exp.getTime() + Days*24*60*60*1000);
        document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
function getCookie(name)
{
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
        if(arr=document.cookie.match(reg)) return unescape(arr[2]);
        else return null;
}
function delCookie(name)
{
    var exp = new Date();
        exp.setTime(exp.getTime() - 1);
    var cval=getCookie(name);
        if(cval!=null) document.cookie= name + "="+cval+";expires="+exp.toGMTString();
}