function photo_close()
{
  document.getElementById('photo_zoom').display='none';
  document.getElementById('photo_zoom').innerHTML = '';
}

function photo_zoom(img_src)
{  
  document.getElementById('photo_zoom').innerHTML = '<img src="'+img_src+'" id="zoom_img" alt="Grande photo de l\'oeuvre" onclick="photo_close()" />';
  document.getElementById('photo_zoom').display='block';
//   document.getElementById('zoom_img').style.top='50px';
//   document.getElementById('zoom_img').style.left='200px';
}