javascript操作cookie

function setCookie(name,value)
{
var Days = 30;
var exp  = new Date();
exp.setTime(exp.getTime() + Days*24*60*60*1000);
document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}

function getCookie(name)
{
var arr = document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)"));
if(arr != null) {
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();
}
}