function ShowHide (el)
{
	if (inst_inst_shown(el)) 
		{
			inst_hide(el);
		} 
		else 
		{
			inst_show(el);
		}
}

function inst_inst_shown(el) 
{
    var element = document.getElementById(el);
    return (element.style.display == 'block');
}

function inst_hide(el)
{
    var element = document.getElementById(el);
    if (element && element.style) element.style.display = 'none';
}

function inst_show(el)
{
    var element = document.getElementById(el);
    if (element && element.style) element.style.display = 'block';
}