function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

function hidePopup() {
  document.getElementById('popupNoHideUntilClick').className = "hiddenElement";
}

function initPopupNoHideUntilClick() {
  var links = document.getElementById('popupNoHideUntilClick').getElementsByTagName('div');

  for(var i=0; i < links.length; i++){
    if (links[i].className.indexOf('adLink1') != -1) {
      links[i].onclick = hidePopup;
    }
  }
}

addLoadEvent(initPopupNoHideUntilClick);