function writeQuantityMinus(id)
{
	document.write('<span onclick="return false;" onmouseup="quantityAdjust(\'' + id + '\', -1);" class="quantityAdjust">-</span>');
}

function writeQuantityPlus(id)
{
	document.write('<span onclick="return false;" onmouseup="quantityAdjust(\'' + id + '\', 1);" class="quantityAdjust">+</span>');
}

function quantityAdjust(id, amount)
{
	var obj = document.getElementById(id);
	if (obj)
	{
		var i = parseInt(obj.value);
		if (isNaN(i)) i = 0;
		i = i + amount;
		if (i < 0) i = 0;
		var max = obj.getAttribute("max");
		if (max)
		{
			if (i > max) i = max;
		}
		obj.value = i;
	}
}