var pActiveItem;

function setItemActive(pItemId) {
	var pItem = getItemFromItemId(pItemId);
	pActiveItem = pItem;
	setClass(pItem, "btn_on");
}

function setItemInactive(pItem) {
	if (pItem != pActiveItem) {
		setClass(pItem, "btn_off");
	}
}

function getItemFromItemId(pItemId)
{
	var pItem = document.getElementById(pItemId);
	return	pItem;
}

function setClass (pItem, sClass)
{
	pItem.className	= sClass;
}