js 中获取制定的cook信息实现方法

function get_cookie(name)    {        var bikky = document.cookie;        name += "=";        var i = 0;        while (i < bikky.length)        {            var offset = i + name.length;            if (bikky.substring(i, offset) == name)            {                var endstr = bikky.indexOf(";", offset);                if (endstr == -1) endstr = bikky.length;                return unescape(bikky.substring(offset, endstr));            }            i = bikky.indexOf(" ", i) + 1;            if (i == 0) break;        }        return null;    }