var targetPos = 0;
var currentPos = 0;

function calcMenuPos() 
{
	var elem = document.getElementById('menu');
//alert(document.body.clientWidth);

	targetPos = document.body.scrollTop - 122;
	if (targetPos < 0) targetPos = 0;

	currentPos = parseInt(elem.style.top);
	if (Math.round(currentPos - targetPos) != 0)
	{
		currentPos =currentPos + (targetPos - currentPos) / 2;
		currentPos = Math.round(currentPos);
		elem.style.top = currentPos+'px';
	}
}
window.setInterval("calcMenuPos()", 100)