diff --git a/src/calibre/gui2/tweak_book/editor/syntax/javascript.py b/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
index 9971e3845c..7f6ab91fae 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
@@ -29,7 +29,7 @@ class JavascriptLexer(RegexLexer):
     modify it.
     """
 
-    flags = re.DOTALL | re.UNICODE | re.MULTILINE
+    flags = re.UNICODE | re.MULTILINE
 
     tokens = {
         b'commentsandwhitespace': [