function setTall() {
	if (document.getElementById && document.getElementById('main') && document.getElementById('leftcol') && document.getElementById('rightcol')) { // Do you know the DOM?
		oMain = document.getElementById('main');
		oLeftcol = document.getElementById('leftcol');
		oRightcol = document.getElementById('rightcol');
		
		var divs = new Array(oLeftcol, oRightcol, oMain);
		var maxHeight = 0;
		
		for (var i = 0; i < divs.length; i++) { // Get the height of the tallest column
			divs[i].style.height = '';
			if (divs[i].offsetHeight + divs[i].offsetTop > maxHeight) maxHeight = divs[i].offsetHeight + divs[i].offsetTop;
		}
	    
		document.getElementById('container').style.height = maxHeight + 'px'; 
		
		
//		if (document.getElementById('container').offsetHeight > maxHeight) { // is the size of the container correct?
//			// correct padding/margin if needed
//			document.getElementById('container').style.height = (maxHeight - (divs[i].offsetHeight - maxHeight)) + 'px';
//		}
			
		oMain.style.height = parseInt(maxHeight - oMain.offsetTop) + 'px';
		oLeftcol.style.height = parseInt(maxHeight - oLeftcol.offsetTop) + 'px';
		oRightcol.style.height = parseInt(maxHeight - oRightcol.offsetTop) + 'px';
	}
}

window.onload = function() {
	setTall();
}

window.onresize = function() {
	setTall();
}
function checkForm(formEl) {
	//checkAantal
	aantalEl = formEl.aantal;
	if (parseInt(aantalEl.getAttribute('min_value')) > parseInt(aantalEl.value)) {
		alert('Van dit artikel dient u minimaal '+aantalEl.getAttribute('min_value')+' stuks te bestellen');
		return false;
	}
	return true;
}