<!--
function rollover(normal,over){
                        this.normal = new Image();
                        this.normal.src = normal;
                        this.over = new Image();
                        this.over.src = over;
                }
                
                function pdover(imgname){
                        if (document.images && imgname != defimg){
                                document[imgname].src = eval(imgname + ".over.src");
                        }
                }
                
                function pdout(imgname){
                        if (document.images && imgname != defimg){
                                document[imgname].src = eval(imgname + ".normal.src");
                        }
                }
                
                function pdchange(imgname){
                        if (document.images){
                                document[defimg].src = eval(defimg + ".normal.src");
                                document[imgname].src = eval(imgname + ".over.src");
                                defimg = imgname;
                        }
                }
                
                var defimg = 'bob';
                var hyett = new rollover("images/hyett.gif","images/hyett_on.gif");
                var eisen = new rollover("images/eisen.gif","images/eisen_on.gif");
                var lang = new rollover("images/lang.gif","images/lang_on.gif");
                var practice1 = new rollover("images/practice1.gif","images/practice1_on.gif");
                var practice2 = new rollover("images/practice2.gif","images/practice2_on.gif");
                var practice3 = new rollover("images/practice3.gif","images/practice3_on.gif");

// -->