if (document.images) {
image1on = new Image(); image1on.src = "boton11.gif"; 
image2on = new Image(); image2on.src = "boton21.gif"; 
image3on = new Image(); image3on.src = "boton31.gif";
image4on = new Image(); image4on.src = "boton41.gif";
image5on = new Image(); image5on.src = "boton51.gif";
image6on = new Image(); image6on.src = "boton61.gif";
image7on = new Image(); image7on.src = "boton71.gif";
image8on = new Image(); image8on.src = "boton81.gif";
image9on = new Image(); image9on.src = "boton91.gif";
imageAon = new Image(); imageAon.src = "botonA1.gif";
image1off = new Image(); image1off.src = "boton1.gif";
image2off = new Image(); image2off.src = "boton2.gif";  
image3off = new Image(); image3off.src = "boton3.gif";
image4off = new Image(); image4off.src = "boton4.gif";
image5off = new Image(); image5off.src = "boton5.gif";
image6off = new Image(); image6off.src = "boton6.gif";
image7off = new Image(); image7off.src = "boton7.gif";
image8off = new Image(); image8off.src = "boton8.gif";
image9off = new Image(); image9off.src = "boton9.gif";
imageAoff = new Image(); imageAoff.src = "botonA.gif";
}
function turnOn(imageName) {
if (document.images) {document[imageName].src = eval(imageName + "on.src");}
}
function turnOff(imageName) {
if (document.images) {document[imageName].src = eval(imageName + "off.src");}
}