图片自动调整的模式

//图片自动调整的模式，1为按比例调整 ，2 按大小调整。 
var resizemode = 1
function imgresize(o)
{
	if (resizemode == 2 || o.onmousewheel)
	{
		if (o.width > 500)
		{
			o.style.width = '500px';
		}
		if (o.height > 800)
		{
			o.style.height = '800px';
		}
	}
	else
	{
		var parentNode = o.parentNode.parentNode
		if (parentNode)
		{
			if (o.offsetWidth >= parentNode.offsetWidth) o.style.width = '98%';
		}
		else
		{
			var parentNode = o.parentNode
			if (parentNode)
			{
				if (o.offsetWidth >= parentNode.offsetWidth) o.style.width = '98%';
			}
		}
	}
}
function bbimg(o)
{
	var zoom = parseInt(o.style.zoom, 10) || 100;
	zoom += event.wheelDelta / 12;
	if (zoom > 0) o.style.zoom = zoom + '%';
	return false;
}
function imgzoom(img, maxsize)
{
	var a = new Image();
	a.src = img.src
	if (a.width > maxsize * 4)
	{
		img.style.width = maxsize;
	}
	else if (a.width >= maxsize)
	{
		img.style.width = Math.round(a.width * Math.floor(4 * maxsize / a.width) / 4);
	}
	return false;
}