var TimeRemaining = 0;
var BaseWidth;
var BaseHeight;
var BaseImage;
var dh;

function DoFlip()
{
	TimeRemaining = 500;
	dh = document.getElementById('dh');
	if (dh)
	{
		BaseWidth = dh.width;
		BaseHeight = dh.height;
		SetNext();
	}
}


function SetNext()
{
var width;
	do {
		width = BaseWidth - 
		Math.sin((Math.PI * (1000 / TimeRemaining)) / 2) * BaseWidth
		TimeRemaining -= 20;
	}
	while (width > BaseWidth && TimeRemaining > 0);

	dh.width = width;
	dh.height = BaseHeight
	if (TimeRemaining > 0)
	{
		setTimeout(SetNext, 40);
	}

}