function setEltDisplay(id, disp) {
    if (!document.getElementById)
	return false;
    var elt = document.getElementById(id);
    if (elt)
	elt.style.display = disp;
    return false;
}

function showElt(id) {setEltDisplay(id, "");return false;}
function hideElt(id) {setEltDisplay(id, "none");return false;}

var currently_visible;
function toggleDisplay(id) 
{
 if (!document.getElementById)
	return false;
    var elt = document.getElementById(id);
    if(elt.style.display == 'none')
        {
            elt.style.display = "";
            //hide others now
            if(currently_visible != null)
                hideElt(currently_visible);
            currently_visible = id;
        }
    else
	elt.style.display = "none";
    return false;
}
function checkSomething (id)
{
    var elt = $(id);
    elt.checked=1;
}
function unCheck (id)
{
    var elt = $(id);
    elt.checked=0;
}
function matchDisplay (id, id2)
{
 if (!document.getElementById)
	return false;
 var elt = document.getElementById(id);
 var elt2 = document.getElementById(id2);
 elt.style.display = elt2.style.display;
}