function go_forward () {
	window.ul.css({right: (parseInt(window.ul.css('right'),10)-window.step)+'px'});
	window.st = window.setTimeout('go_forward();', window.interval);
	if (parseInt(window.ul.css('right'),10)<=-(window.ul.width()-window.c_ul.width())) {
		bt_prev.addClass('prev_none');
		bt_next.removeClass('next_none');
		window.clearTimeout(window.st);
		window.st = window.setTimeout('go_back();', window.interval);
	}
}

function go_back () {
	window.ul.css({right: (parseInt(window.ul.css('right'),10)+window.step)+'px'});
	window.st = window.setTimeout('go_back();', window.interval);
	if (parseInt(window.ul.css('right'),10)>=0) {
		bt_prev.removeClass('prev_none');		
		bt_next.addClass('next_none');
		window.clearTimeout(window.st);
		window.st = window.setTimeout('go_forward();', window.interval);
	}
}
	
$(function(){
	window.step = 2;
	window.interval = 100;
		
	window.c_ul = $("#slider .c_slider");
	window.ul = $("#slider .c_slider ul");
	
	bt_prev = $("#slider .prev");
	bt_next = $("#slider .next");
	bt_next.addClass('next_none');
	
	bt_prev.click(function(){
		if (!$(this).hasClass('prev_none')) {
			bt_prev.addClass('prev_none');
			bt_next.removeClass('next_none');
			window.clearTimeout(window.st);
			window.st = window.setTimeout('go_back();', window.interval);
		}
	});
	bt_next.click(function(){
		if (!$(this).hasClass('next_none')) {
			$(this).addClass('next_none');
			bt_prev.removeClass('prev_none');
			window.clearTimeout(window.st);
			window.st = window.setTimeout('go_forward();', window.interval);
		}
	});
	
	go_forward();
});