//图片按比例缩放
//调用：<img src="图片" onload="javascript:DrawImage(this,150,100);">
var flag = false;
function DrawImage(ImgD,iwidth,iheight)
{
	var image = new Image();
	image.src = ImgD.src;
	if( image.width > 0 && image.height > 0 )
	{
		flag = true;
		if( image.width/image.height >= iwidth/iheight )
		{
			if( image.width > iwidth )
			{ 
				ImgD.width = iwidth;
				ImgD.height = (image.height*iwidth)/image.width;
			}
			else
			{
				ImgD.width = image.width; 
				ImgD.height = image.height;
			}
		}
		else
		{
			if( image.height > iheight )
			{ 
				ImgD.height = iheight;
				ImgD.width = (image.width*iheight)/image.height; 
			}
			else
			{
				ImgD.width = image.width; 
				ImgD.height = image.height;
			}
		}
	}
} 

function ZoomImg(o) 
{ 
      var zoom = parseInt(o.style.zoom, 10) || 100; 
      zoom += event.wheelDelta / 12; 
      if(zoom > 0) 
          o.style.zoom = zoom + '%'; 
      return false; 
}