function make_yellow_left(obj)
{
	obj.firstChild.src = '../img/arrow_left_yellow.png';
}

function make_white_left(obj)
{
	obj.firstChild.src = '../img/arrow_left.png';
}

function make_yellow_right(obj)
{
	obj.firstChild.src = '../img/arrow_right_yellow.png';
}

function make_white_right(obj)
{
	obj.firstChild.src = '../img/arrow_right.png';
}