diff --git a/src/General/UI.coffee b/src/General/UI.coffee
index 2a22e4eca..4c7ccd2b7 100644
--- a/src/General/UI.coffee
+++ b/src/General/UI.coffee
@@ -267,7 +267,7 @@ drag = (e) ->
   left = if left < 10
     0
   else if @width - left < 10
-    null
+    ''
   else
     left / @screenWidth * 100 + '%'
 
@@ -275,19 +275,19 @@ drag = (e) ->
   top = if top < (10 + @topBorder)
     @topBorder + 'px'
   else if @height - top < (10 + @bottomBorder)
-    null
+    ''
   else
     top / @screenHeight * 100 + '%'
 
-  right = if left is null
+  right = if left is ''
     0
   else
-    null
+    ''
 
-  bottom = if top is null
+  bottom = if top is ''
     @bottomBorder + 'px'
   else
-    null
+    ''
 
   {style} = @
   style.left   = left
@@ -356,9 +356,9 @@ hover = (e) ->
   threshold = @clientWidth / 2
   threshold = Math.max threshold, @clientWidth - 400 unless @isImage
   [left, right] = if clientX <= threshold
-    [clientX + 45 + 'px', null]
+    [clientX + 45 + 'px', '']
   else
-    [null, @clientWidth - clientX + 45 + 'px']
+    ['', @clientWidth - clientX + 45 + 'px']
 
   {style} = @
   style.top   = top + 'px'
diff --git a/src/Images/Gallery.coffee b/src/Images/Gallery.coffee
index 38fee7532..8d8f5262b 100644
--- a/src/Images/Gallery.coffee
+++ b/src/Images/Gallery.coffee
@@ -329,7 +329,7 @@ Gallery =
         style.minHeight = minHeight + 'px'
         style.minWidth = (width / height * minHeight) + 'px'
       else
-        style.minHeight = style.minWidth = null
+        style.minHeight = style.minWidth = ''
 
     setDelay: -> Gallery.delay = +@value
 
diff --git a/src/Miscellaneous/Nav.coffee b/src/Miscellaneous/Nav.coffee
index 71227374b..d5a552940 100644
--- a/src/Miscellaneous/Nav.coffee
+++ b/src/Miscellaneous/Nav.coffee
@@ -74,6 +74,6 @@ Nav =
     if extra > 0
       d.body.style.marginBottom = "#{extra}px"
     else
-      d.body.style.marginBottom = null
+      d.body.style.marginBottom = ''
       delete Nav.haveExtra
       $.off d, 'scroll', Nav.removeExtra
diff --git a/src/Posting/Captcha.v1.coffee b/src/Posting/Captcha.v1.coffee
index 577ebd031..3a7f33d75 100644
--- a/src/Posting/Captcha.v1.coffee
+++ b/src/Posting/Captcha.v1.coffee
@@ -135,7 +135,7 @@ Captcha.v1 =
     QR.captcha.load()
 
     if QR.nodes.el.getBoundingClientRect().bottom > doc.clientHeight
-      QR.nodes.el.style.top    = null
+      QR.nodes.el.style.top    = ''
       QR.nodes.el.style.bottom = '0px'
 
   destroy: ->
diff --git a/src/Posting/Captcha.v2.coffee b/src/Posting/Captcha.v2.coffee
index 662ca209c..6c42cc2de 100644
--- a/src/Posting/Captcha.v2.coffee
+++ b/src/Posting/Captcha.v2.coffee
@@ -144,7 +144,7 @@ Captcha.v2 =
 
   fixQRPosition: ->
     if QR.nodes.el.getBoundingClientRect().bottom > doc.clientHeight
-      QR.nodes.el.style.top    = null
+      QR.nodes.el.style.top    = ''
       QR.nodes.el.style.bottom = '0px'
 
   setupTextArea: (textarea) ->
diff --git a/src/Posting/QR.post.coffee b/src/Posting/QR.post.coffee
index 725576c89..f77596d06 100644
--- a/src/Posting/QR.post.coffee
+++ b/src/Posting/QR.post.coffee
@@ -203,7 +203,7 @@ QR.post = class
       @showFileData()
     else
       @updateFilename()
-    @nodes.el.style.backgroundImage = null
+    @nodes.el.style.backgroundImage = ''
     unless @file.type in QR.mimeTypes
       @fileError 'Unsupported file type.'
     else if /^(image|video)\//.test @file.type
@@ -299,7 +299,7 @@ QR.post = class
     delete @filesize
     @nodes.el.removeAttribute 'title'
     QR.nodes.filename.removeAttribute 'title'
-    @nodes.el.style.backgroundImage = null
+    @nodes.el.style.backgroundImage = ''
     $.rmClass @nodes.el, 'has-file'
     @showFileData()
     URL.revokeObjectURL @URL