圖片按比例縮放函數

圖片按比例縮放函數
  
 <script language="JavaScript">
  
 <!--
  
 //圖片按比例縮放
  
 var flag=false;
  
 function DrawImage(ImgD){
  
 var image=new Image();
  
 var iwidth = 150; //定義允許圖片寬度
  
 var iheight = 100; //定義允許圖片高度
  
 image.src=ImgD.src;
  
 if(image.width>0 && image.height>0){
  
 flag=true;
  
 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;
  
 }
  
 }
  
 }
  
 //調用：<img src="圖片" οnlοad="javascript:DrawImage(this)">
  
 //-->
  
 </script>