function showDescription(elem) {
	if(document.layers) {
	    document.layers[elem].visibility = (document.layers[elem].visibility == 'hide') ? 'show' : 'hide';
	}
	else if(document.all) {
	    document.all[elem].style.visibility = (document.all[elem].style.visibility == 'hidden') ? 'visible' : 'hidden';
	}
	else if(document.getElementById) {
	    document.getElementById(elem).style.visibility = (document.getElementById(elem).style.visibility == 'hidden') ? 'visible' : 'hidden';
	}
}