if(document.images) {
 var imgs = new Array();
 imgs[0] = new Image(); imgs[0].src = "../images/home.png"; 
 imgs[1] = new Image(); imgs[1].src = "../images/home_a.png";
 imgs[2] = new Image(); imgs[2].src = "../images/entry.png";
 imgs[3] = new Image(); imgs[3].src = "../images/entry_a.png";
 imgs[4] = new Image(); imgs[4].src = "../images/client.png";
 imgs[5] = new Image(); imgs[5].src = "../images/client_a.png";
 imgs[6] = new Image(); imgs[6].src = "../images/contact.png";
 imgs[7] = new Image(); imgs[7].src = "../images/contact_a.png";


} 
function chgimg(id, imgname) {
 if(document.images) {
  if(imgs[imgname]) {
     document.images[id].src = imgs[imgname].src;
  }
  else {
     document.images[id].src = imgname;
   }
  }
 }