if (document.images) {
productoff=new Image();
productoff.src= "images/menu/productoff.jpg";
producton=new Image();
producton.src= "images/menu/producton.jpg";
supportoff=new Image();
supportoff.src= "images/menu/supportoff.jpg";
supporton=new Image();
supporton.src= "images/menu/supporton.jpg";
aboutoff=new Image();
aboutoff.src= "images/menu/aboutoff.jpg";
abouton=new Image();
abouton.src= "images/menu/abouton.jpg";
contactoff=new Image();
contactoff.src= "images/menu/contactoff.jpg";
contacton=new Image();
contacton.src= "images/menu/contacton.jpg";
blogoff=new Image();
blogoff.src= "images/menu/blogoff.jpg";
blogon=new Image();
blogon.src= "images/menu/blogon.jpg";

}

function imageOn (imagename){
  document[imagename].src=eval(imagename+"on.src");
 }
function imageOff (imagename){
  document[imagename].src=eval(imagename+"off.src");
 }