function setMouseHover() {
  if(!document.getElementsByTagName) return false;
  var buttons = getElementsByClass(document,"mapbutton","img");
  var butcount = buttons.length;
  for (var i=0; i<buttons.length; i++) {
    buttons[i].onmouseover = function() {
      this.setAttribute("src", "/images/button-2.png");
    }
    buttons[i].onmouseout = function() {
      this.setAttribute("src", "/images/button-1.png");
    }
  }
}

addLoadEvent(setMouseHover);

function preparePopupLinks() {
  var links = document.getElementsByTagName("a");
  for( var i=0; i<links.length; i++ ) {
    var index = links[i].className.indexOf("popup");
    if( index > -1 ) {
      links[i].onclick = function() {
        newWindow = window.open(this.href, "popup", "width=600, height=550");
        return false;
      }
    }
  }
}

addLoadEvent(preparePopupLinks);

window.onunload = function() {
  newWindow.close();
}