function show(elementId) {
	var el = document.getElementById(elementId);

	var i = el.className.indexOf('invisible');
	if (i >= 0)
		el.className = el.className.substring(0, i)
			+ 'visible'
			+ el.className.substring(i + 9);
	else
		if ((i = el.className.indexOf('visible')) == -1)
			el.className += (el.className == '' ? '' : ' ') + 'visible';
}

function hide(element) {
	var el;
	if (typeof(element) == 'String')
	  el = document.getElementById(elementId);
	else
		el = element;

	var i = el.className.indexOf('invisible');
	if (i == -1)
		if ((i = el.className.indexOf('visible')) >= 0)
			el.className = el.className.substring(0, i)
				+ 'invisible'
				+ el.className.substring(i + 7);
		else
			el.className += (el.className == '' ? '' : ' ') + 'invisible';
}