(function($) {
   var isTransitioned = true;
   var transparent = 0;
   var translucent = 0.3;
   var opaque = 1;

   var fade = function() {
      if(isTransitioned) {
         isTransitioned = false;
         if(1000 < $(document).scrollTop()) {
            $("#gototop").show().fadeTo("slow", translucent, function() {
               isTransitioned = true;
            });
         } else {
            $("#gototop").fadeTo("slow", transparent, function() {
               isTransitioned = true;
               $(this).hide();
            });
         }
      }
   }

   $(function() {
      $("body").prepend('<a id="top"></a>\n<a href="#top" id="gototop" class="gototop">Top of page</a>');

      fade();
      $(document).scroll(fade);

      $("#gototop").fadeTo(0,translucent);

      $("#gototop").click(function() {
         $.scrollTo(0, 750);
         $(this).fadeOut();
         return false;
      });

      $("#gototop").mouseover(function() {
         if(isTransitioned) {
            $(this).fadeTo("slow",opaque);
         }
      }).mouseout(function() {
         if(isTransitioned) {
            $(this).fadeTo("slow",translucent);
         }
      });
   });
})(jQuery);