if (document.images) {
  smtopOff = new Image();
  smtopOff.src = "sm_menu/smtop_logom_homeOff.gif";
  smtopOn = new Image();
  smtopOn.src = "sm_menu/smtop_logom_homeOn.gif";
}
function on(imgName) {
	if (document.images) {
		imgOn = eval(imgName + "On.src");
    document [imgName].src = imgOn;
  }
}
function off(imgName) {
	if (document.images) {
		imgOff = eval(imgName + "Off.src");
    document [imgName].src = imgOff;
  }
}