得到cookie值

function GetCookie(sName)
{  
    //alert( document.cookie);
    var aCookie = document.cookie.split("; ");
    for (var i=0; i < aCookie.length; i++)
    {
       var aCrumb = aCookie[i].split("=");
       if (sName == aCrumb[0])
       {
        if (aCrumb.length > 1 )
         return unescape(aCrumb[1]);
        else
         return "";
       }
    }
    return null;
}