var currentSlide = 1;

function hideDiv(which) {
	document.getElementById("slide"+which).style.zIndex = 1;
	new Effect.Opacity("slide"+which, { from: 1, to: 0 });
}
function showDiv(which) {
	document.getElementById("slide"+which).style.zIndex = 50;
	new Effect.Opacity("slide"+which, { from: 0, to: 1 });
}

function prepare(num) {
	for(i=1; i <= num; i++) {
		hideDiv(i);
	}
	hideDiv("-1");
	rotation=setTimeout("rotate("+num+")",5000);
}

function rotate(num) {
    if (currentSlide < num) {
		showDiv(currentSlide+1);
		hideDiv(currentSlide);
		currentSlide = currentSlide + 1;
	}
	else{
		showDiv(1);
		hideDiv(num);
		currentSlide = 1;
	}
	rotation=setTimeout("rotate("+num+")",5000);
}

function stopRotation(stopwhich){
	if(stopwhich != currentSlide){
		showDiv(stopwhich);
		hideDiv(currentSlide);
		currentSlide = stopwhich;
	}
	clearTimeout(rotation);
}