diff --git a/setup/check.py b/setup/check.py
index 9142de27c1..538f33289c 100644
--- a/setup/check.py
+++ b/setup/check.py
@@ -63,11 +63,14 @@ class Check(Command):
             for f in x[-1]:
                 y = self.j(x[0], f)
                 mtime = os.stat(y).st_mtime
-                if (f.endswith('.py') and f not in ('ptempfile.py', 'feedparser.py',
+                if cache.get(y, 0) == mtime:
+                    continue
+                if (f.endswith('.py') and f not in ('feedparser.py',
                     'pyparsing.py', 'markdown.py') and
-                    'genshi' not in y and cache.get(y, 0) != mtime and
                     'prs500/driver.py' not in y):
                         yield y, mtime
+                if f.endswith('.coffee'):
+                    yield y, mtime
 
         for x in os.walk(self.j(self.d(self.SRC), 'recipes')):
             for f in x[-1]:
@@ -84,9 +87,20 @@ class Check(Command):
         builtins = list(set_builtins(self.BUILTINS))
         for f, mtime in self.get_files(cache):
             self.info('\tChecking', f)
-            w = check_for_python_errors(open(f, 'rb').read(), f)
-            if w:
-                self.report_errors(w)
+            errors = False
+            ext = os.path.splitext(f)[1]
+            if ext in {'.py', '.recipe'}:
+                w = check_for_python_errors(open(f, 'rb').read(), f)
+                if w:
+                    errors = True
+                    self.report_errors(w)
+            else:
+                try:
+                    subprocess.check_call(['coffee', '-c', '-p', f],
+                            stdout=open(os.devnull, 'wb'))
+                except:
+                    errors = True
+            if errors:
                 cPickle.dump(cache, open(self.CACHE, 'wb'), -1)
                 subprocess.call(['gvim', '-f', f])
                 raise SystemExit(1)
diff --git a/src/calibre/ebooks/oeb/display/cfi.coffee b/src/calibre/ebooks/oeb/display/cfi.coffee
index 1bb2533485..511f8fa300 100644
--- a/src/calibre/ebooks/oeb/display/cfi.coffee
+++ b/src/calibre/ebooks/oeb/display/cfi.coffee
@@ -133,7 +133,15 @@ find_offset_for_point = (x, y, node, cdoc) ->
 class CanonicalFragmentIdentifier
 
     # This class is a namespace to expose CFI functions via the window.cfi
-    # object
+    # object. The three most important functions are:
+    #
+    # is_compatible(): Throws an error if the browser is not compatible with
+    #                  this script
+    #
+    # at(x, y): which maps a point to a CFI, if possible
+    #
+    # scroll_to(cfi): which scrolls the browser to a point corresponding to the
+    #                 given cfi, and returns the x and y co-ordinates of the point.
 
     constructor: () -> # {{{
         this.CREATE_RANGE_ERR = "Your browser does not support the createRange function. Update it to a newer version."
diff --git a/src/calibre/ebooks/oeb/display/test/index.html b/src/calibre/ebooks/oeb/display/test/index.html
index afeae055a4..e5d8eea491 100644
--- a/src/calibre/ebooks/oeb/display/test/index.html
+++ b/src/calibre/ebooks/oeb/display/test/index.html
@@ -5,7 +5,10 @@
         <script type="text/javascript" src="cfi.coffee"></script>
         <script type="text/javascript" src="cfi-test.coffee"></script>
         <style type="text/css">
-            body { font-family: sans-serif }
+            body { 
+                font-family: sans-serif;
+                background-color: white;
+            }
 
             h2 {
                 border-top: solid 2px black;