function toggle(slId,mId)
{
    if(document.getElementById)
    {
        slv = document.getElementById(slId);
        mst = document.getElementById(mId);

        if (slv.style.display == "none") {
            slv.style.display = "";
            mst.style.backgroundImage = "url(im/minus.gif)";
        } else {
            slv.style.display = "none";
            mst.style.backgroundImage = "url(im/plus.gif)";
        }
    }
}