//自動縮圖
var flag=false; 
function DrawImage(ImgD,set_w,set_h){
var image=new Image(); 
image.src=ImgD.src; 
if(image.width>0 && image.height>0){ 
  flag=true; 
  if(image.width<=set_w && image.height<=set_h){
	ImgD.width=image.width;
	ImgD.height=image.height;
  }
  else if(image.width>image.height){
	ImgD.width=set_w;
	ImgD.height=image.height/image.width*set_w;
  }
  else{
	ImgD.height=set_h;
	ImgD.width=image.width/image.height*set_h;
  }
}
}