function openWindow (url)
{
	var params = 'width=700,height=500,location=1,menubar=1,toolbar=0,resizable=1,scrollbars=1';
	
	if (url) {
		var refWin = window.open(url, 'refWin', params);
		refWin.focus();
	}
}
function changeImage(id, src)
{
	var image;
	if (image = document.getElementById(id)) {
		image.setAttribute('src', src);
	}
}
function changeClass(id, newClass)
{
	var element;
	if (element = document.getElementById(id)) {
		element.className = newClass;
	}
}