var timer = null;
var delay = 60;

preloadImage('bubble.png');

function preloadImage(image)
{
	var src = 'images/' + image;
	var image = new Image();

	image.onerror = function ()
	{
		alert(src);
	}

	image.src = src;
}

function showBubble()
{
	document.getElementById('bubble').style.display = 'block';

	timer = window.setTimeout('shakeLayer();', delay);
}

var n = 20;

function shakeLayer()
{
	window.clearTimeout(timer);

	if (n > 0)
	{
		var bubble = document.getElementById('bubble');

		if (n % 2 == 0)
		{
			bubble.style.left = (bubble.offsetLeft + 2) + 'px';
			bubble.style.top = (bubble.offsetTop + 6) + 'px';
		}
		else
		{
			bubble.style.left = (bubble.offsetLeft - 2) + 'px';
			bubble.style.top = (bubble.offsetTop - 6) + 'px';
		}

		n -= 1;

		timer = window.setTimeout('shakeLayer();', delay);
	}
}