function changeImage(id,src,height,last)
{
	img = document.getElementById('main_image');
	img.style.marginTop = Math.round((583-height)/2)+"px";
	img.src = "img/gallery/"+src;
	img.alt = id;
	
	document.getElementById('thumb_'+id+'_bottom').style.backgroundImage = 'url(img/gallery/thumbs/'+src+')';
	document.getElementById('thumb_'+id+'_top').style.display = 'none';
	document.getElementById('thumb_'+last+'_top').style.display = 'block';

	
}
function quantityChange(direction,box_id)
{
	var box = document.getElementById("quan_box"+box_id);
	var currentValue = box.value;
	if(direction == "up")
	{
		box.value = parseInt(currentValue)+1;
	}
	else
	{
		proposedValue = parseInt(currentValue)-1;
		if(proposedValue < 1)
		{
			box.value = 0;
		}
		else
		{
			box.value = proposedValue;
		}
	}
}