function equalheight() {
	var height_1 = document.getElementById('left').offsetHeight;
	var height_2 = document.getElementById('right').offsetHeight;
	var maxheight = height_1;
	if (height_2 >= maxheight) {
		maxheight = height_2;
	}
	document.getElementById('left').style.height = maxheight + 'px';
	document.getElementById('right').style.height = maxheight + 'px';
}

document.onload = equalheight();