function changeImage(obj) {
  var mainImage = document.getElementById("mainImage");
  mainImage.src = obj.src;

}
function initView(el_id, view_item_count, style)
{
	var menu = document.getElementById(el_id);
	var menu_list = menu.getElementsByTagName('li');
	var menu_count = menu_list.length;
	style = (typeof(style) != 'undefined') ? style : 'block';

	for(var i=0;i<menu_count;i++){
		if(i<view_item_count) menu_list[i].style.display = style;
		else menu_list[i].style.display = 'none';
	}
}

function moveList(direction, el_id, view_item_count, scroll_count, style)
{
	var menu = document.getElementById(el_id);
	var menu_list = menu.getElementsByTagName('li');
	var menu_count = menu_list.length;
	var start_no = 0;

	style = (typeof(style) != 'undefined') ? style : 'block';

	// ÇöÀç º¸¿©Áö°í ÀÖ´Â ¿¤¸®¸ÕÆ®ÀÇ ½ÃÀÛÀ» È®ÀÎ
	for(var i=0;i<menu_count;i++){
		if(menu_list[i].style.display == style){
			start_no = i;
			break;
		}
	}
	
	// ¹æÇâ¿¡ µû¸¥ À̵¿
	if(direction == 'next'){
		if(menu_list[menu_count-1].style.display == style) return false;
		else{
			for(var i=0;i<menu_count;i++){
				if(i>=start_no + scroll_count && i<start_no + scroll_count + view_item_count){
					menu_list[i].style.display = style;
				}else{
					menu_list[i].style.display = 'none';
				}
			}
		}
	}else if(direction == 'prev'){
		if(menu_list[0].style.display == style) return false;
		else{
			for(var i=0;i<menu_count;i++){
				if(i>=start_no - scroll_count && i<start_no - scroll_count + view_item_count){
					menu_list[i].style.display = style;
				}else{
					menu_list[i].style.display = 'none';
				}
			}
		}
	}
}