// JScript 文件

 function scalePhoto(imgId,width,height){
    var img = document.getElementById(imgId);
   
  if(img != null){
 
  var imgWidth = img.width;
  var imgHeight = img.height; 
  if(imgWidth>width&&imgHeight>height){
   //both image's width and height are larger than required one
   var widthRate = imgWidth/width;
   var heightRate = imgHeight/height;
   if(widthRate>heightRate){
    //use width to retrieve the image
    img.width=width;
    img.height=imgHeight*(width/imgWidth);
   }else{
    img.height=height;
    img.width=imgWidth*(height/imgHeight);
   }   
  }
  else if(imgWidth>width){
   //the image width lg than the required width
   img.width=width;
   img.height=imgHeight*(width/imgWidth);
  }
  else if(imgHeight>height){
   //the image height lg than the required
   img.height=height;
   img.width=imgWidth*(height/imgHeight); 
  }  
 }
}