var lastTile='';

function $(s){ return document.getElementById(s); };

function showTile(oTarget)
{
	var tileName = oTarget.getAttribute("rel");
	var curTile;
	if (lastTile!='')
	       lastTile.style.display="none";
	curTile = $(tileName);
	curTile.style.display="block";
	lastTile = curTile;
	if (window.event)
		window.event.cancelBubble = true;
	return false;
}

function showHide(oTarget){
	if (oTarget.style.display == 'none')
	       oTarget.style.display = 'block';
	else
	       oTarget.style.display = 'none';
}

/* guides for algorithms */
 var guidesOn = false;
 function toggleStyles()
 {
	var g = $('toggleGuidesText');
	var s = $('guideStyles');
	if (!s) return;
	guidesOn = s.disabled = !s.disabled;
	if (guidesOn)
		g.innerHTML = "guides off";
	else
		g.innerHTML = "guides on";
}

 var printOn = false;
 function togglePrintVersion()
 {
	var g = $('btnTogglePrintVersion');
	var s = $('mainStyles');
	if (!s) return;
	printOn = !(s.disabled = !s.disabled);
	if (printOn)
		g.value = "printable version";
	else
		g.value = "normal version";
}

function onLoadActions(){
	if (!document.getElementById)
		return false;
	showTile($('link1'));
	$('btnToggleGuides').onclick=toggleStyles;
	$('btnTogglePrintVersion').onclick=togglePrintVersion;
}
window.onload = onLoadActions;