function btnOn(id,x,y,c)
{
  btn = document.getElementById(id);
  btn.style.backgroundPosition = x+"px "+y+"px";
  btn.style.color = c;
}

function btnOff(id,x,y,c)
{
  btn = document.getElementById(id);
  btn.style.backgroundPosition = x+"px "+y+"px";
  btn.style.color = c;
}

function switchPic(new_url,new_txt)
{
  /* var element = document.getElementById("bigpicdiv");
  element.style.left = pos+'px'; */

  var element = document.getElementById("bigpic");
  element.src = new_url;
  
  var element = document.getElementById("bigpictxtdiv");
  element.innerHTML = new_txt;
  
}