function SetTopButton (id)
{
	var element = document.getElementById(id);
	
	if (element)
	{
		element.className = 'active';
	}
}

function PercentageCalculator (value, maxvalue, percentage, type)
{
	var result = null;
	
	switch (type)
	{
		// increase
		case "+":
		{
			result = value - ((value / 100) * percentage);
			
			break;
		}
		// decrease
		case "-":
		{
			result = value + (((maxvalue - value) / 100) * percentage);
			
			break;
		}
	}
	
	return result;
}