no need to rush

src/General/Main.coffee

@@ -144,11 +144,6 @@ Main =
 
     return unless Conf['Show Support Message']
     <% if (type === 'userscript') { %>
-    test = $.el 'span'
-    test.classList.add 'a', 'b'
-    if test.className isnt 'a b'
-      new Notice 'warning', "Your version of Firefox is outdated (v<%= meta.min.firefox %> minimum) and <%= meta.name %> may not operate correctly.", 30
-
     GMver = GM_info.version.split '.'
     for v, i in "<%= meta.min.greasemonkey %>".split '.'
       continue if v is GMver[i]

src/General/lib/$.coffee

@@ -115,11 +115,13 @@ $.X = (path, root) ->
   # XPathResult.ORDERED_NODE_SNAPSHOT_TYPE === 7
   d.evaluate path, root, null, 7, null
 
-$.addClass = (el, className...) ->
-  el.classList.add className...
+$.addClass = (el, classNames...) ->
+  el.classList.add className for className in classNames
+  return
 
-$.rmClass = (el, className...) ->
-  el.classList.remove className...
+$.rmClass = (el, classNames...) ->
+  el.classList.remove className for className in classNames
+  return
 
 $.toggleClass = (el, className) ->
   el.classList.toggle className