if (document.images) {            // Active Images
img1on = new Image(); 
img1on.src ="images/home-on.gif"; 
img1off = new Image(); 
img1off.src ="images/home-off.gif";
img2on = new Image(); 
img2on.src ="images/services-on.gif"; 
img2off = new Image(); 
img2off.src ="images/services-off.gif"; 
img3on = new Image(); 
img3on.src ="images/projects-on.gif"; 
img3off = new Image(); 
img3off.src ="images/projects-off.gif";
img4on = new Image(); 
img4on.src ="images/bios-on.gif"; 
img4off = new Image(); 
img4off.src ="images/bios-off.gif"; 
img5on = new Image(); 
img5on.src ="images/contact-us-on.gif"; 
img5off = new Image(); 
img5off.src ="images/contact-us-off.gif";
img6on = new Image(); 
img6on.src ="images/links-on.gif"; 
img6off = new Image(); 
img6off.src ="images/links-off.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");
       }
}