//使用方法<img>里加入onload="javascript:DrawImage(this,宽,高);"
// JavaScript Document
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;  
        }  
}  
}  
}