1 files changed, 5 insertions, 4 deletions
diff --git a/app/assets/javascripts/build.js b/app/assets/javascripts/build.js
index 74babedae89..1dfa064acfd 100644
--- a/app/assets/javascripts/build.js
+++ b/app/assets/javascripts/build.js
@@ -64,9 +64,10 @@ window.Build = (function () {
     $(window)
       .off('scroll')
       .on('scroll', () => {
-        if (this.$buildTraceOutput.prop('scrollHeight') > this.windowSize) {
+        const contentHeight = this.$buildTraceOutput.prop('scrollHeight');
+        if (contentHeight > this.windowSize) {
           // means the user did not scroll, the content was updated.
-          this.windowSize = this.$buildTraceOutput.prop('scrollHeight');
+          this.windowSize = contentHeight;
         } else {
           // User scrolled
           this.hasBeenScrolled = true;
@@ -113,7 +114,7 @@ window.Build = (function () {
 
     if (this.canScroll()) {
       if (currentPosition > 0 &&
-        (document.body.scrollHeight - document.body.scrollTop !== windowHeight)) {
+        (document.body.scrollHeight - currentPosition !== windowHeight)) {
       // User is in the middle of the log
 
         this.toggleDisableButton(this.$scrollTopBtn, false);
@@ -123,7 +124,7 @@ window.Build = (function () {
 
         this.toggleDisableButton(this.$scrollTopBtn, true);
         this.toggleDisableButton(this.$scrollBottomBtn, false);
-      } else if (document.body.scrollHeight - document.body.scrollTop === windowHeight) {
+      } else if (document.body.scrollHeight - currentPosition === windowHeight) {
         // User is at the bottom of the build log.
 
         this.toggleDisableButton(this.$scrollTopBtn, false);