function updateTooltip (e) {
	scrollTop =  Math.max (document.body.scrollTop,  document.documentElement.scrollTop);
	scrollLeft = Math.max (document.body.scrollLeft, document.documentElement.scrollLeft);
	x = (document.all) ? window.event.clientX + scrollLeft : e.pageX;
	y = (document.all) ? window.event.clientY + scrollTop  : e.pageY;
	if (tooltip != null) {
		tooltip.style.left = (x + 10) + "px";
		tooltip.style.top  = (y + 10) + "px";
	}
}

function showTooltip (txt) {
	tooltip = document.getElementById ('tooltip');
	tooltip.innerHTML = txt;
	tooltip.style.display = 'block';
	document.onmousemove = updateTooltip;
}

function hideTooltip () {
	tooltip.style.display = "none";
	document.onmousemove = null;
}