if (document.images) {
img1on = new Image();
img1on.src = "images/blogoon.gif";
img1off = new Image();
img1off.src ="images/blogooff.gif";
img2on = new Image();
img2on.src = "images/bbeneon.gif";
img2off = new Image();
img2off.src ="images/bbeneoff.gif";
img3on = new Image();
img3on.src = "images/binfoon.gif";
img3off = new Image();
img3off.src ="images/binfooff.gif";
img4on = new Image();
img4on.src = "images/bconton.gif";
img4off = new Image();
img4off.src ="images/bcontoff.gif";
}
function imgOn(imgName) {
 if (document.images) {
  document[imgName].src = eval(imgName + "on.src");
 }
}
function imgOff(imgName) {
 if (document.images) {
  document[imgName].src = eval(imgName + "off.src");
 }
}