
<!-- 
//图片按比例缩放 

function changeImg(ImgD,iwidth,iheight,offsetmiddle,marginbottom){ 
 var image=new Image(); 
// var iwidth = 200;  //定义允许图片宽度 
// var iheight =200;  //定义允许图片高度 
 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; 
  } 
 } 
 
 //if(ImgD.width>image.width) ImgD.width=image.width;
  //if(ImgD.height=image.height) ImgD.height=image.height;
 
 if(offsetmiddle==null) offsetmiddle=-1;
if(offsetmiddle!=-1) ImgD.style.marginTop=((iheight-ImgD.height)/2+offsetmiddle)+"px";

if(marginbottom)  ImgD.style.marginBottom=(iheight-ImgD.height)/2+"px";
}  
//-->