// 按比例缩放图
function DrawImage(ImgD,iw,ih){
	var image=new Image();
	var iwidth = iw; //200; //定义允许图片宽度
	var iheight = ih;//200; //定义允许图片高度

	
	image.src=ImgD.src;
	if(image.width>0 && image.height>0)
	{
		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;
			}
		}
		
		ImgD.style.display = "inline"
	}
}