var dom = (document.getElementById) ? true : false;
var ns5 = ((navigator.userAgent.indexOf("Gecko")>-1) && dom) ? true: false;
var ie5 = ((navigator.userAgent.indexOf("MSIE")>-1) && dom) ? true : false;
var ns4 = (document.layers && !dom) ? true : false;
var ie4 = (document.all && !dom) ? true : false;
var nodyn = (!ns5 && !ns4 && !ie4 && !ie5) ? true : false;
// avoid error of passing event object in older browsers
if (nodyn) { event = "nope" }

// settings for tooltip 
var offX= 20;
var offY= 12; 

////////////////////////////////////////////////////////////
//  initTip	- initialization for tooltip.
////////////////////////////////////////////////////////////
var tooltip, tipcss;
function initTip() {
	if (nodyn) return;
	tooltip = (ns4)? document.tipDiv.document: (ie4)? document.all['tipDiv']: (ie5||ns5)? document.getElementById('tipDiv'): null;
	tipcss = (ns4)? document.tipDiv: tooltip.style;
}

window.onload = initTip;

/////////////////////////////////////////////////
//  doTooltip function
//			Assembles content for tooltip and writes 
//			it to tipDiv
/////////////////////////////////////////////////
function doTooltip(evt) {
	var tg = (evt.target) ? evt.target : evt.srcElement
	if (ns4) {
		var tip = '<img src="' + tg.id + '">';
		tooltip.write(tip);
		tooltip.close();
	} else if (ie4||ie5||ns5) {
		var tip = '<img src="' + tg.id + '">';
	 	tooltip.innerHTML = tip;
	}
	positionTip(evt);
}

/////////////////////////////////////////////////////////////
//  positionTip function
//		Calculations use mouseover event position, 
//		offset amounts and tooltip width to position
//		tooltip within window.
/////////////////////////////////////////////////////////////
function positionTip(evt) {
	mouseX = (ns4||ns5)? evt.pageX: window.event.clientX + document.body.scrollLeft;
	mouseY = (ns4||ns5)? evt.pageY: window.event.clientY + document.body.scrollTop;
	// tooltip width and height
	var tpWd = (ns4)? tooltip.width: (ie4||ie5)? tooltip.clientWidth: tooltip.offsetWidth;
	var tpHt = (ns4)? tooltip.height: (ie4||ie5)? tooltip.clientHeight: tooltip.offsetHeight;
	// document area in view (subtract scrollbar width for ns)
	var winWd = (ns4||ns5)? window.innerWidth-20+window.pageXOffset: document.body.clientWidth+document.body.scrollLeft;
	var winHt = (ns4||ns5)? window.innerHeight-20+window.pageYOffset: document.body.clientHeight+document.body.scrollTop;
	// check mouse position against tip and window dimensions
	// and position the tooltip 
	if ((mouseX+offX+tpWd)>winWd) 
		tipcss.left = (ns4)? mouseX-(tpWd+offX): mouseX-(tpWd+offX)+"px";
	else tipcss.left = (ns4)? mouseX+offX: mouseX+offX+"px";
	if ((mouseY+offY+tpHt)>winHt) 
		tipcss.top = (ns4)? winHt-(tpHt+offY): winHt-(tpHt+offY)+"px";
	else tipcss.top = (ns4)? mouseY+offY: mouseY+offY+"px";
	t1=setTimeout("tipcss.visibility='visible'",100);
}

function hideTip() {
	if (!tooltip) return;
	t2=setTimeout("tipcss.visibility='hidden'",100);
	tipOn = false;
}