[балерун]

пардон, код забыл вложить

<style>
	#container
	{
		margin-top: 60px;
		position: absolute;
		width: 2000px;
	}

	.day
	{
		position: relative;
		display: inline;
	}

	.day h2
	{
		padding: 0 5px;
		position: absolute;
		left: 4px;
		top: -65px;
	}

	.event
	{
		width: 50px;
		height: 50px;
		border: 1px solid black;
		margin: 0 4px;
		display: inline-block;
	}
</style>
<script>
	window.addEventListener('load', function(){
		var container = document.getElementById('container');
		var compStyle = window.getComputedStyle(container.getElementsByClassName('day')[1], null);
		alert('width: ' + compStyle.width)
	}, false)
</script>
<div id="container">
	<div class="day">
		<h2>День 1</h2>
		<div data-event-id="0" class="event">1</div>
		<div data-event-id="1" class="event">2</div>
		<div data-event-id="2" class="event">3</div>
		<div data-event-id="3" class="event">4</div>
	</div>

	<div class="day">
		<h2>День 2</h2>
		<div data-event-id="4" class="event">1</div>
		<div data-event-id="5" class="event">2</div>
	</div>
</div>