JavaScrip操作Cookie

//生成cookie
function addCookie(sName, sValue, day) {
    var expireDate = new Date();
    expireDate.setDate(expireDate.getDate() + day);
    //设置失效时间 
    document.cookie = escape(sName) + '=' + escape(sValue) + ';expires=' + expireDate.toGMTString()+';path=/';

}
//读取sid
function getCookie(cookieName) {
    if (document.cookie.length > 0) {
        var cStart = document.cookie.indexOf(cookieName + "=");
        if (cStart != -1) {
            cStart = cStart + cookieName.length + 1;
            var cEnd = document.cookie.indexOf(";", cStart);
            if (cEnd == -1)
                cEnd = document.cookie.length;
            return unescape(document.cookie.substring(cStart, cEnd));
        }
    }
    return "";
}