if (document.images) {
  var nav1 = new Image();
  nav1.src = "images/nav1.gif";
  var nav2 = new Image();
  nav2.src = "images/nav2.gif";
  var nav3 = new Image();
  nav3.src = "images/nav3.gif";
  var nav4 = new Image();
  nav4.src = "images/nav4.gif";
  var nav5 = new Image();
  nav5.src = "images/nav5.gif";
  var navproj1 = new Image();
  navproj1.src = "images/navproj1.gif";
  var navproj2 = new Image();
  navproj2.src = "images/navproj2.gif";
  var navproj3 = new Image();
  navproj3.src = "images/navproj3.gif";
  var navproj4 = new Image();
  navproj4.src = "images/navproj4.gif";
  var navproj5 = new Image();
  navproj5.src = "images/navproj5.gif";
  var navproj6 = new Image();
  navproj6.src = "images/navproj6.gif";
  var navproj7 = new Image();
  navproj7.src = "images/navproj7.gif";
  var mainImage = new Image();
 mainImage.src = "images/blog/whatis.jpg";
  
  
  var nav1a = new Image();
  nav1a.src = "images/nav1a.gif";
  var nav2a = new Image();
  nav2a.src = "images/nav2a.gif";
  var nav3a = new Image();
  nav3a.src = "images/nav3a.gif";
  var nav4a = new Image();
  nav4a.src = "images/nav4a.gif";
  var nav5a = new Image();
  nav5a.src = "images/nav5a.gif";
  var navproj1a = new Image();
  navproj1a.src = "images/navproj1a.gif";
  var navproj2a = new Image();
  navproj2a.src = "images/navproj2a.gif";
  var navproj3a = new Image();
  navproj3a.src = "images/navproj3a.gif";
  var navproj4a = new Image();
  navproj4a.src = "images/navproj4a.gif";
  var navproj5a = new Image();
  navproj5a.src = "images/navproj5a.gif";
  var navproj6a = new Image();
  navproj6a.src = "images/navproj6a.gif";
  var navproj7a = new Image();
  navproj7a.src = "images/navproj7a.gif";
  var mainImagea = new Image();
  mainImagea.src = "images/blog/whatis.jpg";
  
  
}

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

function offNav(imgName) {
  if (document.images)
    document.images[imgName].src = eval(imgName + "a.src");
}