var   flag=false;   
  function   DrawImage(ImgD,iwidth,iheight){   
  //参数(图片,宽度,高度)   
  var   image=new   Image();   
  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;   
  }   
  }   
  else{   
  if(image.height>iheight){     
  ImgD.height=iheight;   
  ImgD.width=(image.width*iheight)/image.height;     
  }else{   
  ImgD.width=image.width;     
  ImgD.height=image.height;   
  }   
  }   
  }   
  }