// toggle visibility 
function toggle(theDiv) {
  var elem = document.getElementById(theDiv);
  elem.style.display = (elem.style.display == "none")?"":"none";
}

// open window
function pop(URL) { //v2.0
  window.open(URL,'','status=yes,scrollbars=yes,resizable=yes,width=500,height=600');
}

function show(id){
	el = document.getElementById(id);
	if (el.style.display == 'none')
	{
		el.style.display = '';
	} else {
		el.style.display = 'none';
	}
}

function swapimage(img){
    // old school image swap
    var src = document.images[img].src;
    document.images[img].src = (src.match("add"))?"elements/subtract.png":"elements/add.png"; 
}