var currentlyDisplayedElement = false;

function ToggleDisplay(elementId) 
{
	var element = document.getElementById(elementId);
	if (element)
	{
		if (element.style.display == 'none')
		{
			if (currentlyDisplayedElement)
			{
				currentlyDisplayedElement.style.display = 'none';
			}
			element.style.display = 'block';
			currentlyDisplayedElement = element;
		}
		else
		{
			element.style.display = 'none';
			currentlyDisplayedElement = false;
		}
	}
}