function toggle_display(id)
{
	var el = document.getElementById(id);
	if (el.style.display != 'none' )
	{
		el.style.display = 'none';
	}

	else
	{
		el.style.display = '';
	}
}
	

function add_load_event(func)
{
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	}
	else
	{
		window.onload = function()
		{
			oldonload();
			func();
		}
	}
}

function get_parent_by_tag_name(node, tagName)
{
	var parent = node.parentNode;
	var strTagName = new String(parent.tagName);
	if (strTagName.toLowerCase() == tagName)
		return parent
	else
		return get_parent_by_tag_name(parent, tagName)
}