javascript等比例缩放控制图片(转的)

Code:

<script lauguage="javascript">
function resizeimg(ImgD,iwidth,iheight) {
    var image=new Image();
    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;
               }
              ImgD.alt=image.width+""+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.alt=image.width+""+image.height;
           }
ImgD.style.cursor= "pointer"; //ıָ
ImgD.onclick = function() { window.open(this.src);} //