function tr_on(id)
{
	var tr = document.getElementById(id);

	if (/^menu/.test(tr.className))
		tr.className = 'h' + tr.className;
}

function tr_off(id)
{
	var tr = document.getElementById(id);

	if (tr.className.substr(0, 1) == 'h')
		tr.className = tr.className.substr(1);
}