diff --git a/cps/static/js/kthoom.js b/cps/static/js/kthoom.js
index 3fbb22d3..b1ba0882 100644
--- a/cps/static/js/kthoom.js
+++ b/cps/static/js/kthoom.js
@@ -803,7 +803,7 @@ function init(filename) {
     });
 
     // Scrolling up/down will update current image if a new image is into view (for Long Strip Display)
-    $("#mainContent").scroll(function (event){
+    $("#mainContent").scroll(function (){
         var scroll = $("#mainContent").scrollTop();
         var viewLength = 0;
         $(".mainImage").each(function(){
@@ -815,8 +815,11 @@ function init(filename) {
             //Scroll Down
             if (currentImage + 1 < imageFiles.length) {
                 if (currentImageOffset(currentImage + 1) <= 1) {
-                    currentImage++;
-                    console.log(Math.round(imageFiles.length / viewLength * scroll, 0));
+                    currentImage = Math.floor((imageFiles.length) / (viewLength-viewLength/(imageFiles.length)) * scroll, 0);
+                    if ( currentImage >= imageFiles.length) {
+                        currentImage = imageFiles.length - 1;
+                    }
+                    console.log(currentImage);
                     scrollTocToActive();
                     updateProgress();
                 }
@@ -825,14 +828,13 @@ function init(filename) {
             //Scroll Up
             if (currentImage - 1 > -1) {
                 if (currentImageOffset(currentImage - 1) >= 0) {
-                    currentImage--;
-                    console.log(Math.round(imageFiles.length / viewLength * scroll, 0));
+                    currentImage = Math.floor((imageFiles.length) / (viewLength-viewLength/(imageFiles.length)) * scroll, 0);
+                    console.log(currentImage);
                     scrollTocToActive();
                     updateProgress();
                 }
             }
         }
-
         // Update scroll position
         prevScrollPosition = scroll;
     });
diff --git a/cps/tornado_wsgi.py b/cps/tornado_wsgi.py
index 289e0d37..c1571ece 100644
--- a/cps/tornado_wsgi.py
+++ b/cps/tornado_wsgi.py
@@ -24,7 +24,7 @@ from tornado import httputil
 from tornado.ioloop import IOLoop
 
 from typing import List, Tuple, Optional, Callable, Any, Dict, Text
-from types import TracebackType, FunctionType
+from types import TracebackType
 import typing
 
 if typing.TYPE_CHECKING:
@@ -34,7 +34,7 @@ if typing.TYPE_CHECKING:
 class MyWSGIContainer(WSGIContainer):
 
     def __call__(self, request: httputil.HTTPServerRequest) -> None:
-        if tornado.version_info < (6, 2, 0, 0):
+        if tornado.version_info < (6, 3, 0, -99):
             data = {}  # type: Dict[str, Any]
             response = []  # type: List[bytes]