var newsBaseDivOffset = 120;
var displayedNbLines = 1;
var currentFinalMargin = 0;
var newsDivOffset = 0;
var newsDivScrollingInterval = null;
var newsDivScrollingDelay = 20;
var newsDivScrollingStep = 20;

function scrollNewsDiv()
{
	currentMargin = document.getElementById('scrollingNewsWindowDiv').style.marginTop;
	currentMargin = currentMargin.replace('px', '');
	currentMargin = parseInt(currentMargin);
	if (isNaN(currentMargin))
		currentMargin = 0;
	if (newsDivOffset < 0)
		currentMargin = Math.max(currentMargin - newsDivScrollingStep, currentFinalMargin);
	else
		currentMargin = Math.min(currentMargin + newsDivScrollingStep, currentFinalMargin);
	if (currentMargin == currentFinalMargin)
		clearInterval(newsDivScrollingInterval);
	document.getElementById('scrollingNewsWindowDiv').style.marginTop = currentMargin + 'px';
}

function scrollUpNewsDiv(maxNblines)
{
	newsDivOffset = newsBaseDivOffset;
	currentFinalMargin = Math.min((maxNblines - displayedNbLines) *  newsDivOffset, (currentFinalMargin + newsDivOffset));
	newsDivScrollingInterval = setInterval('scrollNewsDiv()', newsDivScrollingDelay);
	if (currentFinalMargin > -newsDivOffset)
		document.getElementById('scrollingNewsPrevious').style.display = 'none';
	if (maxNblines > displayedNbLines)
		document.getElementById('scrollingNewsNext').style.display = 'inline';
}
function scrollDownNewsDiv(maxNblines)
{
	newsDivOffset = -newsBaseDivOffset;
	currentFinalMargin = Math.max((maxNblines - displayedNbLines) *  newsDivOffset, (currentFinalMargin + newsDivOffset));
	newsDivScrollingInterval = setInterval('scrollNewsDiv()', newsDivScrollingDelay);
	if (currentFinalMargin <= newsDivOffset)
		document.getElementById('scrollingNewsPrevious').style.display = 'inline';
	if (currentFinalMargin <= (maxNblines - displayedNbLines) *  newsDivOffset)
		document.getElementById('scrollingNewsNext').style.display = 'none';
}