Event.observe(window, "load", function() {
  $$('.navigation img').each(function(image) {
    image.observe('mouseover', function(event) {
      this.src = this.src.gsub(/_inactive/, "_active");
    });
  
    image.observe('mouseout', function(event) {
      if (!this.hasClassName("active")) {
        this.src = this.src.gsub(/_active/, "_inactive");
      }
    });
  });
  
  $('kitailogo').observe('mouseover', function(event) {
    this.src = '/images/kitai_logo_active.png';
  });
  
  $('kitailogo').observe('mouseout', function(event) {
    this.src = '/images/kitai_logo.png';
  });
  
});