function conmouseover(el,step){
	if (el._drInterval){
		clearInterval (el._drInterval);
	}	
	
	var parent_h = document.getElementById('scroll-list').offsetHeight;
	
	el._drInterval = setInterval (function(){
		var node = document.getElementById ('list-contents');
		var t = parseInt (node.offsetTop);
		var b = parseInt(node.offsetBottom);
		var h = parseInt(node.offsetHeight);
		
		if ((step >= 0 && t >= 0) || (step <= 0 && t <= -(h - parent_h))) {
			return;
		}
		node.style.top = node.offsetTop + step + 'px';
	}, 50);
}

function conmouseout(el){
	clearInterval (el._drInterval);
}

function setcscrolltop(el) {
	var node = document.getElementById ('list-contents');
	node.style.top = '0px';
}

function setcscrollbottom(el) {
	var node = document.getElementById ('list-contents');
	var parent_h = document.getElementById('scroll-list').offsetHeight;
	var h = parseInt(node.offsetHeight);
	
	node.style.top = -(h - parent_h) + 'px';
}