diff --git a/boards/static/js/thread_update.js b/boards/static/js/thread_update.js
--- a/boards/static/js/thread_update.js
+++ b/boards/static/js/thread_update.js
@@ -118,7 +118,7 @@ function blink(node) {
 
 function isPageBottom() {
     var scroll = $(window).scrollTop() / ($(document).height()
-        - $(window).height())
+        - $(window).height());
 
     return scroll == 1
 }