var scroll = 0;
var scrolling = false;
var content = document.getElementById('content');
var scrollup = document.getElementById('scrollup');
var scrolldown = document.getElementById('scrolldown');

function startscroll(inv) {
	if (scrolling == false) {
		startofscroll = setInterval('omegascroll('+inv+')', 100);
		//if (inv > 0) scrolldown.className = 'scroll_active';
		//if (inv < 0) scrollup.className = 'scroll_active';
	}
	scrolling = true;
}

function omegascroll(inv) {
	scroll = scroll-inv;
	if (scroll > 0) scroll = 0;
	if (scroll < -(content.offsetHeight-290)) scroll = -(content.offsetHeight-290);
	content.style.marginTop = scroll+'px';
}

function stopscroll() {
	clearInterval(startofscroll);
	scrolling = false;
}