function getElemRefs(id) 
{
    var el = (document.getElementById)? document.getElementById(id): (document.all)? document.all[id]: (document.layers)? document.layers[id]: null;
    if (el) el.css = (el.style)? el.style: el;
    return el;
}

function displayLayer(id) 
{
    var lyr = getElemRefs(id);
    if (lyr && lyr.css) lyr.css.display = "block";
}

function dontDisplayLayer(id) 
{
    var lyr = getElemRefs(id);
    if (lyr && lyr.css) lyr.css.display = "none";
}

function toggleDisplayLayer(id) 
{
    var lyr = getElemRefs(id);
    if (lyr.css.display == "none")
    {
        displayLayer(id);
    }
    else 
    {
        dontDisplayLayer(id);
    }
}