if (document.images) {            // Active Images
            img1on = new Image();      
            img1on.src = "images/nav_homeOn.gif"; 
            img2on = new Image(); 
            img2on.src = "images/nav_historyOn.gif";  
            img3on = new Image();
            img3on.src = "images/nav_aboutOn.gif";
            img4on = new Image();
            img4on.src = "images/nav_mediaOn.gif";
            img5on = new Image();
            img5on.src = "images/nav_directionOn.gif";
         
            img1off = new Image(); 
            img1off.src = "images/nav_home.gif"; 
            img2off = new Image();          
            img2off.src = "images/nav_history.gif"; 
            img3off = new Image();
            img3off.src = "images/nav_about.gif";
            img4off = new Image();
            img4off.src = "images/nav_media.gif";
	    img5off = new Image();
            img5off.src = "images/nav_direction.gif";
        }


// Function to 'activate' images.
         
function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");
        }
}
         
// Function to 'deactivate' images.
         
function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}