if (document.images) {            // Active Images
            img1on = new Image();      
            img1on.src = "imagenes/caract_on.gif"; 
            img2on = new Image(); 
            img2on.src = "imagenes/acceso_on.gif";
            img3on = new Image(); 
            img3on.src = "imagenes/fct_on.gif";
            img4on = new Image(); 
            img4on.src = "imagenes/glosario_on.gif";
            img5on = new Image(); 
            img5on.src = "imagenes/ciclos_on.gif";
            img6on = new Image(); 
            img6on.src = "imagenes/familias_on.gif";
            img7on = new Image(); 
            img7on.src = "imagenes/centros_on.gif";
            img8on = new Image(); 
            img8on.src = "imagenes/garantia_on.gif";
            img9on = new Image(); 
            img9on.src = "imagenes/solicitud_on.gif";
            img10on = new Image(); 
            img10on.src = "imagenes/portada_on.gif";
            
            
            
            
            
            
           
            


            img1off = new Image();      
            img1off.src = "imagenes/caract_off.gif"; 
            img2off = new Image(); 
            img2off.src = "imagenes/acceso_off.gif";
            img3off = new Image(); 
            img3off.src = "imagenes/fct_off.gif";
            img4off = new Image(); 
            img4off.src = "imagenes/glosario_off.gif";
            img5off = new Image(); 
            img5off.src = "imagenes/ciclos_off.gif";
            img6off = new Image(); 
            img6off.src = "imagenes/familias_off.gif";
            img7off = new Image(); 
            img7off.src = "imagenes/centros_off.gif";
            img8off = new Image(); 
            img8off.src = "imagenes/garantia_off.gif";
            img9off = new Image(); 
            img9off.src = "imagenes/solicitud_off.gif";
            img10off = new Image(); 
            img10off.src = "imagenes/portada_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");
        }
}