function addDropdown(toggleElement, linkElement, buttonDiv, buttonImageName) {
  if(document.getElementById(toggleElement) != null) {
  
    var toggleElement = new Fx.Slide(toggleElement, {link: 'cancel'}).hide();

    $(linkElement).addEvent('mouseenter', function(e) {
      var buttonURL = 'url(/assets/images/icons/' + buttonImageName + '_hover.gif) no-repeat';
      $(buttonDiv).setStyle('background', buttonURL);
      e = new Event(e);
      toggleElement.show();
      e.stop();
    });
    
    $(linkElement).addEvent('mouseleave', function(e) {
      var buttonURL = 'url(/assets/images/buttons/' + buttonImageName + '.gif) no-repeat';
      $(buttonDiv).setStyle('background', buttonURL);
      e = new Event(e);
      toggleElement.hide();
      e.stop();
    });  
  }
}
  
window.addEvent('domready', function() {    
  addDropdown('marineMenuDropdown','marineHome','marineButton','marine_sectors');  
  addDropdown('forestryMenuDropdown','forestryHome','forestryButton','forestry_sectors');  
  addDropdown('marineMenuDropdown_grey','marineHome_grey','marineButton_grey','industriesMarine_sectors');  
  addDropdown('forestryMenuDropdown_grey','forestryHome_grey','forestryButton_grey','industriesForestry_sectors');  
});