// ͼƬµÈ±ÈÀýËõ·Å
function zoom(imgname,widths,heights){ 
	var w; 
	var h; 
	
	w=imgname.width; 
	h=imgname.height;
	if(imgname.width>widths){ 
		do 
			w=w-1; 
		while (w>widths); 
	
		s=w/imgname.width; 
 
		imgname.width=w; 
		imgname.height=h*s; 
		h=imgname.height 
		xw=w;
		yh=h*s;
	} 

	if(imgname.height>heights){ 
		do 
			h=h-1; 
		while (h>heights) ; 
		
		s=h/imgname.height; 
		
		imgname.width=w*s; 
		imgname.height=heights; 
		xw=w*s;
		yh=heights;
	}
	h = imgname.height;
	if ((h%2)!=0)  imgname.height=h+1;
	// return {x:xw,y:yh};
}