function preload() {
        this.length = preload.arguments.length;
        for (var i = 0; i < this.length; i++) {
                this[i+1] = new Image();
                this[i+1].src = preload.arguments[i];
        }
}

var testme = navigator.userAgent;
if (testme.indexOf("Mozilla/3.0",0) >= 0) {
        var stuff = new preload(
  "images/navcomputeroff.gif",
  "images/navcontactoff.gif",
  "images/navglobaloff.gif",  
  "images/navhomeoff.gif",
  "images/navwebsiteoff.gif",
  "images/navsharpoff.gif")
}