var home_on = new Image();
 home_on.src = "images/home_on.gif";
 var home = new Image();
 home.src = "images/home.gif";

 var about_on = new Image();
 about_on.src = "images/about_on.gif";
 var about = new Image();
 about.src = "images/about.gif";

 var services_on = new Image();
 services_on.src = "images/services_on.gif";
 var services = new Image();
 services.src = "images/services.gif";

 var portfolio_on = new Image();
 portfolio_on.src = "images/portfolio_on.gif";
 var portfolio = new Image();
 portfolio.src = "images/portfolio.gif";

 var links_on = new Image();
 links_on.src = "images/links_on.gif";
 var links = new Image();
 links.src = "images/links.gif";
 
 var contact_on = new Image();
 contact_on.src = "images/contact_on.gif";
 var contact = new Image();
 contact.src = "images/contact.gif";

window.onerror = null

  function mouseover(imgName,newImg)
 {
  if (document.images) document.images[imgName].src = eval(newImg + ".src");
 }