var mouseY = 0;
var viewMiddle = 0;
var maxH = 0;

window.addEvent('load', function() {
	if($('deckeliContainer')) {
		
		var viewH 		= $('deckeliView').getSize().y;
		viewMiddle	= viewH/2;
		maxH 		= $('deckeliContainer').getSize().y - viewH + 5;
		$('deckeliView').addEvent('mousemove', getMousePosition);
		animateDeckeli.periodical(40);
		$('scrollup').setStyle('opacity', 0.5);
		$('scrolldown').setStyle('opacity', 0.5);
		$('scrollup').addEvents({
			'mouseenter': function() {
				this.setStyle('opacity', 1);
			}, 
			'mouseleave': function() {
				this.setStyle('opacity', 0.5);
			}
		});
		$('scrolldown').addEvents({
			'mouseenter': function() {
				this.setStyle('opacity', 1);
			}, 
			'mouseleave': function() {
				this.setStyle('opacity', 0.5);
			}
		});

	}
});

function getMousePosition(event) {
	mouseY = event.page.y -210; // Werte zwischen 0 und 570
}

function animateDeckeli() {
	var delta = viewMiddle - mouseY;
	var t = parseInt($('deckeliContainer').getStyle('margin-top'));
	t += Math.round(delta/50);
	if(t > 0)
		t = 0;
	if(t < -maxH)
		t = -maxH;
	$('deckeliContainer').setStyle('margin-top', t);
}