function preloadImages(base_url)
{
  if (document.images)
  {
    main_over= new Image(119, 60);
    main_over.src=base_url+"images/menu_main_over.png";
    main_out= new Image(119, 60);
    main_out.src=base_url+"images/menu_main_out.png";
  
    news_over= new Image(114, 60);
    news_over.src=base_url+"images/menu_news_over.png";
    news_out= new Image(114, 60);
    news_out.src=base_url+"images/menu_news_out.png";

    products_over= new Image(112, 60);
    products_over.src=base_url+"images/menu_products_over.png";
    products_out= new Image(112, 60);
    products_out.src=base_url+"images/menu_products_out.png";

    howto_over= new Image(119, 60);
    howto_over.src=base_url+"images/menu_howto_over.png";
    howto_out= new Image(119, 60);
    howto_out.src=base_url+"images/menu_howto_out.png";
    
    about_over= new Image(98, 60);
    about_over.src=base_url+"images/menu_about_over.png";
    about_out= new Image(98, 60);
    about_out.src=base_url+"images/menu_about_out.png";
  
    career_over= new Image(93, 60);
    career_over.src=base_url+"images/menu_career_over.png";
    career_out= new Image(93, 60);
    career_out.src=base_url+"images/menu_career_out.png";

    contacts_over= new Image(109, 60);
    contacts_over.src=base_url+"images/menu_contacts_over.png";
    contacts_out= new Image(109, 60);
    contacts_out.src=base_url+"images/menu_contacts_out.png";
  }
}

function showOver(img_name)
{
  if (document.images)
  {
    image_over=eval(img_name + "_over.src");
    document[img_name].src= image_over;
  }
}

function showOut(img_name)
{
  if (document.images)
  {
    image_over=eval(img_name + "_out.src");
    document[img_name].src= image_over;
  }
}