if (document.images) {            // Active Images
            img0on = new Image();      
            img0on.src = "imagenes/menu_01_over.png"; 
            img1on = new Image();      
            img1on.src = "imagenes/menu_02_over.png"; 
            img2on = new Image(); 
            img2on.src = "imagenes/menu_03_over.png";
            img3on = new Image(); 
            img3on.src = "imagenes/menu_04_over.png";
            img4on = new Image(); 
            img4on.src = "imagenes/menu_05_over.png";
            img5on = new Image(); 
            img5on.src = "imagenes/menu_06_over.png";
            img6on = new Image();      
            img6on.src = "imagenes/index_menutxt_01_on.png"; 
            img7on = new Image(); 
            img7on.src = "imagenes/index_menutxt_02_on.png";
            img8on = new Image(); 
            img8on.src = "imagenes/index_menutxt_03_on.png";
            img9on = new Image(); 
            img9on.src = "imagenes/index_menutxt_04_on.png";
            img10on = new Image(); 
            img10on.src = "imagenes/index_menutxt_05_on.png";
            
            img0off = new Image();      
            img0off.src = "imagenes/menu_01_off.png";
            img1off = new Image();      
            img1off.src = "imagenes/menu_02_off.png"; 
            img2off = new Image(); 
            img2off.src = "imagenes/menu_03_off.png";
            img3off = new Image(); 
            img3off.src = "imagenes/menu_04_off.png";
            img4off = new Image(); 
            img4off.src = "imagenes/menu_05_off.png";
            img5off = new Image(); 
            img5off.src = "imagenes/menu_06_off.png";
            img6off = new Image();      
            img6off.src = "imagenes/index_menutxt_01.png"; 
            img7off = new Image(); 
            img7off.src = "imagenes/index_menutxt_02.png";
            img8off = new Image(); 
            img8off.src = "imagenes/index_menutxt_03.png";
            img9off = new Image(); 
            img9off.src = "imagenes/index_menutxt_04.png";
            img10off = new Image(); 
            img10off.src = "imagenes/index_menutxt_05.png";
            
        }

// 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");
        }
}