// scroll the element vertically based on its width and the slider maximum value
function scrollVertical(value, element, slider) {
	element.scrollTop = Math.round(value/slider.maximum*(element.scrollHeight-element.offsetHeight));
}

// mouse wheel code from http://adomas.org/javascript-mouse-wheel/
function handle(delta) {
	slider.setValueBy(-delta);
}

function moveScroll(dir) {
	if(dir == 1) {
		//slider value decreases
		if(slider.value != 0) {
			slider.setValue(slider.value -1);
		}
	}
	else if(dir == -1) {
		//slider value increases
		if(slider.value != 100) {
			slider.setValue(slider.value + 1);
		}
	}
}

/** Event handler for mouse wheel event. */
function wheel(event){
	var delta = 0;
	if (!event) /* For IE. */
		event = window.event;
	if (event.wheelDelta) { /* IE/Opera. */
		delta = event.wheelDelta/120;
		/** In Opera 9, delta differs in sign as compared to IE. */
		if (window.opera)
			delta = -delta;
	} else if (event.detail) { /** Mozilla case. */
		/** In Mozilla, sign of delta is different than in IE.
		* Also, delta is multiple of 3.
		*/
		delta = -event.detail/3;
	}

	/** If delta is nonzero, handle it.
	* Basically, delta is now positive if wheel was scrolled up,
	* and negative, if wheel was scrolled down.
	*/
	if (delta)
		handle(delta);

	/** Prevent default actions caused by mouse wheel.
	* That might be ugly, but we handle scrolls somehow
	* anyway, so don't bother here..
	*/
	if (event.preventDefault)
		event.preventDefault();
	
	event.returnValue = false;
}