function show(imgID) {
    document.getElementById(imgID).style.visibility="visible";
}

function hide(imgID) {
    document.getElementById(imgID).style.visibility="hidden";
}

function reloadImage() {   
    var i = Math.round(Math.random()*5)+1;
    
    document.getElementById("leftBarIm").src = 'images/im' + i.toString() + '.jpg';
} 

function toggleAbstract(talkIndex) {
  s = document.getElementById(talkIndex);

  if (s.style.display == 'none') {
    s.style.display = 'block';
  } else if (s.style.display == 'block') {
    s.style.display = 'none';
  }
}