// Detect if browser is Netscape 3 + or IE 4 +.
bName = navigator.appName;
bVer = parseInt(navigator.appVersion);
    if ((bName == "Netscape" && bVer >= 3) || 
        (bName == "Microsoft Internet Explorer" && bVer >= 4)) br = "n3"; 
    else br = "n2";
    
// Create image objects, preload all active, inactive and info images.

    // Create image objects for active images
    if (br== "n3") {
    link1on = new Image();          
    link1on.src = "/art/interior_levels/header/links/home_on.gif"; 
    link2on = new Image(); 
    link2on.src = "/art/interior_levels/header/links/news_info_on.gif"; 
    link3on = new Image();          
    link3on.src = "/art/interior_levels/header/links/observatories_on.gif"; 
    link4on = new Image(); 
    link4on.src = "/art/interior_levels/header/links/r_d_on.gif"; 
    link5on = new Image();          
    link5on.src = "/art/interior_levels/header/links/data_on.gif"; 
    link6on = new Image(); 
    link6on.src = "/art/interior_levels/header/links/marine_ops_on.gif"; 
    link7on = new Image(); 
    link7on.src = "/art/interior_levels/header/links/search_on.gif"; 

    // Create image objects for inactive images
    link1off = new Image();         
    link1off.src = "/art/interior_levels/header/links/home_off.gif"; 
    link2off = new Image(); 
    link2off.src = "/art/interior_levels/header/links/news_info_off.gif"; 
    link3off = new Image();         
    link3off.src = "/art/interior_levels/header/links/observatories_off.gif"; 
    link4off = new Image(); 
    link4off.src = "/art/interior_levels/header/links/r_d_off.gif"; 
    link5off = new Image();         
    link5off.src = "/art/interior_levels/header/links/data_off.gif"; 
    link6off = new Image(); 
    link6off.src = "/art/interior_levels/header/links/marine_ops_off.gif"; 
    link7off = new Image(); 
    link7off.src = "/art/interior_levels/header/links/search_off.gif"; 

    // Create image objects for info field
    link1info = new Image();         
    link1info.src = "/art/interior_levels/header/info_field/home.gif"; 
    link2info = new Image();
    link2info.src = "/art/interior_levels/header/info_field/news_info.gif";
    link3info = new Image();         
    link3info.src = "/art/interior_levels/header/info_field/observatories.gif";
    link4info = new Image();
    link4info.src = "/art/interior_levels/header/info_field/r_d.gif";
    link5info = new Image();         
    link5info.src = "/art/interior_levels/header/info_field/data.gif";
    link6info = new Image();
    link6info.src = "/art/interior_levels/header/info_field/marine_ops.gif";
    link7info = new Image();
    link7info.src = "/art/interior_levels/header/info_field/search.gif";
    }

// Function to "activate" images.
function imgOn(imgName) {
    if (br== "n3") {
    document[imgName].src = eval(imgName + "on.src");
    document["infofield"].src = eval(imgName + "info.src");
    }
}

// Function to "deactivate" images.
function imgOff(imgName) {
    if (br== "n3") {
    document[imgName].src = eval(imgName + "off.src");
    document["infofield"].src = "/art/interior_levels/header/info_field/blank.gif";
    }
}

// function that displays status bar message
function dm(msgStr) {
  document.returnValue = false;
  if (document.images) { 
     window.status = msgStr;
     document.returnValue = true;
  }
}