原生cookie写法

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, 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();}