window.onload = function() 
{
	if(document.getElementById("ll"))
	{
		var left = document.getElementById("ll"); 
	}
	else
	{
		return false; 
	}
	
	if(document.getElementById("rr"))
	{
		var right = document.getElementById("rr");				
	}
	else
	{
		return false;
	}
	
	var h_left = left.offsetHeight;
	var h_right = right.offsetHeight;
	
	//h_left = h_left + 50;
	
	if (h_left <= h_right)
	{
		left.style.height = h_right+"px";
	} 
	else
	{
		right.style.height = h_left+"px";
	}
}

function check_quantity()
{
	var quantity = document.getElementById('quantity').value;
	
	if( isBlank(quantity) )
	{
		alert('Please enter a quantity.');
		return false;
	}
	else
	{
		return true;
	}
}