js实现图片等比缩放

<script language="Javascript" type="text/javascript">
 <!-- 
function drawImage(ImgD,FitWidth,FitHeight){
     var image=new Image();
     image.src=ImgD.src;
     if(image.width>0 && image.height>0){
         if(image.width/image.height>= FitWidth/FitHeight){
             if(image.width>FitWidth){
                 ImgD.width=FitWidth;
                 ImgD.height=(image.height*FitWidth)/image.width;
             }else{
                 ImgD.width=image.width; 
                ImgD.height=image.height;
             }
         } else{
             if(image.height>FitHeight){
                 ImgD.height=FitHeight;
                 ImgD.width=(image.width*FitHeight)/image.height;
             }else{
                 ImgD.width=image.width; 
                ImgD.height=image.height;
             } 
        }
     }
 }
 //-->
 </script>
  

应用：
<img src="XXXX" alt="自动缩放后的效果" width="200" height="200" οnlοad="javascript:DrawImage(this,"200","200");" />

这里给图片设置了固定的大小。用了JS函数以后，不影响效果：）