JS获取Cookie的值

function getCookie(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;
}