/**
 * function to switch background-image of an extra navigation button (those gray ones at subpages)
 * @param String LayID
 * @return void
 */
function sBg(LayID)
{
	var myDiv = document.getElementById(LayID);
	var isInv = false;
	
	if (myDiv.style.backgroundImage.indexOf("url(./images/bg_sub_navi_extra_inv.gif)") != -1) {
		isInv = true;
	}
	if (!isInv && myDiv.style.backgroundImage == '') {
		isInv = false; // happens only on first load
	}
	if (!isInv) {
		myDiv.style.backgroundImage = 'url(./images/bg_sub_navi_extra_inv.gif)';
		myDiv.style.backgroundRepeat = 'repeat-x';
		myDiv.style.backgroundPosition = '0 0';
	} else {
		myDiv.style.backgroundImage = 'url(./images/bg_sub_navi_extra.gif)'
		myDiv.style.backgroundRepeat = 'repeat-x';
		myDiv.style.backgroundPosition = '0 0';
	}
}

function toggleDisplay(layID) {
	var myLayer = document.getElementById(layID);
	if (myLayer.style.display=="none") {
		myLayer.style.display="";
	} else {
		myLayer.style.display="none";
	}
}