<script>
(function(){
  gotop.addEventListener("click",scrollWindow);
  function scrollWindow(){  
 var speed = 1;
 var start = document.body.scrollTop;
 (function doit(){ 
      window.scrollTo(0, document.body.scrollTop - speed);
      if(document.body.scrollTop > start/2){
   speed = speed * 1.02;
          setTimeout(doit,0);  
  }else{
   if(speed / 1.02 > 1 && document.body.scrollTop > 0)speed = speed / 1.01;
          if(document.body.scrollTop > 0)setTimeout(doit,0);   
  }
 })();
 };
})();
</script>

My issue is with website JavaScript code working on every browser but Firefox. I have a button at the bottom of my forum page to return the user to the top. It is enabled with smooth scroll and uses only a small bit of JavaScript, not Jquery. In every other browser, the page slides smoothly back up to the top. In Firefox, it jumps up abruptly; no scroll. While typing this, I don't see any options for enclosing the code in tags, so I'll try to place it here as is, and perhaps you can advise as to why Firefox won't play nice with the code? <pre><nowiki> <script> (function(){ gotop.addEventListener("click",scrollWindow); function scrollWindow(){ var speed = 1; var start = document.body.scrollTop; (function doit(){ window.scrollTo(0, document.body.scrollTop - speed); if(document.body.scrollTop > start/2){ speed = speed * 1.02; setTimeout(doit,0); }else{ if(speed / 1.02 > 1 && document.body.scrollTop > 0)speed = speed / 1.01; if(document.body.scrollTop > 0)setTimeout(doit,0); } })(); }; })(); </script></nowiki></pre> I only have Ad Blocker Plus and Ghostery installed but this has been happening ever since I installed FF with no add-ons. It's FireFox 47.0 (Mac). Thank you for any help.