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();
}
//使用示例
//setCookie("name", "hayden");
//alert(getCookie("name"));
//如果需要设定自定义过期时间
//那么把上面的setCookie　函数换成下面两个函数就ok;
//程序代码
function setCookie(name, value, time) {
    var strsec = getsec(time);
    var exp = new Date();
    exp.setTime(exp.getTime() + strsec * 1);
    document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString();
}
function getsec(str) {
    //alert(str);
    var str1 = str.substring(1, str.length) * 1;
    var str2 = str.substring(0, 1);
    if (str2 == "s") {
        return str1 * 1000;
    }
    else if (str2 == "h") {
        return str1 * 60 * 60 * 1000;
    }
    else if (str2 == "d") {
        return str1 * 24 * 60 * 60 * 1000;
    }
}
function getCookie(name) {
    var arr, reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");
    if (arr = document.cookie.match(reg))
        return unescape(arr[2]);
    else
        return null;
}
//function SetWebChatCookie(eid, resid) {
//    var cookieName = "WebChatAssistant_" + eid
//    var cookieValue = getCookie(cookieName);
//    if (cookieValue == null || cookieValue == "null") {
//        cookieValue = resid;
//        setCookie(cookieName, cookieValue, "d2");
//    }
//    else {
//        if (cookieValue.indexOf(resid) == -1) {//不要有重复的Resid
//            cookieValue += "," + resid;
//            setCookie(cookieName, cookieValue, "d2");
//        }
//    }

//}
//function GetWebChatCookie(eid) {
//    var cookieName = "WebChatAssistant_" + eid;
//    var cookieValue = getCookie(cookieName);
//    return cookieValue;
//}
//这是有设定过期时间的使用示例：
//s20是代表20秒
//h是指小时，如12小时则是：h12
//d是天数，30天则：d30
//setCookie("name", "hayden", "s20");