diff --git a/assets/javascripts/app.js b/assets/javascripts/app.js
index 31b51aa..ba3854b 100644
--- a/assets/javascripts/app.js
+++ b/assets/javascripts/app.js
@@ -9,7 +9,7 @@
     if ( $('.header-banner').length != 0) {
       $('.layout-header').css('height', '');
       var scrollTop = $(window).scrollTop();
-      var scrollBottom = $('html').height() - $(window).height() - 50 - $('.kenjohn').height();
+      var scrollBottom = $('html').height() - $(window).height() - $('.kenjohn').height()*2;
       if (scrollTop>50 && scrollBottom>0)  {          /* 要滑動到選單的距離 */
         $('.kenjohn').addClass('navFixed').removeClass('navRel');   /* 幫選單加上固定效果 */
       } else {