var total_height = 0;
var moved_by = 0;
var sliding_box_time;

function sliding_setup(by,speed) {
	if (by == null) by = 1;
	if (speed == null) speed = 75;

	if ($('bulletin_board_moving_panel').getDimensions().height <= $('bulletin_board').getDimensions().height)
		return false;

	var f = $$('#bulletin_board_moving_panel')[0];
	f.makePositioned();
	total_height = f.getDimensions().height;
	sliding_box_time = setTimeout('move_up('+by+')',speed);
}

function move_up(by,speed) {
	if (by == null) by = 1;
	if (speed == null) speed = 75;
	moved_by += by;
	var f = $$('#bulletin_board_moving_panel')[0];
	if (moved_by >= total_height) {
		moved_by = 0 - $('bulletin_board').getDimensions().height;
		f.style.top =  $('bulletin_board').getDimensions().height + 'px';
	} else
		f.style.top = f.style.top.replace(/px/,'') - by + 'px';
	sliding_box_time = setTimeout('move_up('+by+')',speed);
}

function stop_sliding_box() {
	clearTimeout(sliding_box_time);
}