// this file contains all javascript variables and functions which 
    // must be accessable globally (independent from the current load state 
    // of single html documents or frames)
    //
    // a second (quite important) set of ActivVissionTools javascript 
    // functions are defined in the file '/avt-navbar.html'; there are 
    // functions for explicitely changing images of the navigation-bar and 
    // thus depend on the load state of the navigation frame; 
    // however when changing functions here, please also have a look at the 
    // functions in the file '/avt-navbar.html';

    // global variable which asssigns that we work within a frame environment
    // (this variable is checked before any of the frame-specific functions 
    // or variables is used; thus we won't get any errors, if HTML pages are 
    // loaded directly outside the frame environment)
    var frame_env = true;

    // global variable which asssigns the load state of all navigation objects
    var avtnavbar_loaded = false;

    // global variables which asssign the state of the navigation buttons
    var act_overview = false;
    var act_application = false;
    var act_news = false;
    var act_now = false;
    var act_download = false;
    var act_sales = false;
    var act_support = false;
    var act_family = false;
    var act_documentation = false;
    var act_brochure = false;
    var act_site_map = false;
    var act_home = false;

    // global variable which contains the frame index for application example:
    var appl_idx = 0;

    // reset the state of all buttons to default ('not active')
    function reset_all_buttons_state()
    {
      act_overview = false;
      act_application = false;
      act_news = false;
      act_now = false;
      act_download = false;
      act_sales = false;
      act_support = false;
      act_family = false;
      act_documentation = false;
      act_brochure = false;
      act_site_map = false;
      act_home = false;
     }

    // function for changing only the state of a button to 'active' 
    // (by resetting the state of all others) without changing the image 
    // of any button object; in contrast to set_button_active_img_state this 
    // function can be called savely even if the navigation bar 
    // (and all its button objects) are not already available (rendered)
    function set_button_active_state(code)
    {
      // reset all others:
      reset_all_buttons_state();

      // set single button active:
      if(code == "overview")           act_overview = true;
      else if(code == "application")   act_application = true;
      else if(code == "news")          act_news = true;
      else if(code == "now")           act_now = true;
      else if(code == "download")      act_download = true;
      else if(code == "sales")         act_sales = true;
      else if(code == "support")       act_support = true;
      else if(code == "family")        act_family = true;
      else if(code == "documentation") act_documentation = true;
      else if(code == "brochure")      act_brochure = true;
      else if(code == "site-map")      act_site_map = true;
      else if(code == "home")          act_home = true;
    }