diff --git a/lib/markdown2.py b/lib/markdown2.py
index 3a5d5d9b..471106c4 100755
--- a/lib/markdown2.py
+++ b/lib/markdown2.py
@@ -2169,7 +2169,7 @@ def _encode_amps_and_angles(self, text):
     def _encode_incomplete_tags(self, text):
         if self.safe_mode not in ("replace", "escape"):
             return text
-
+        re.sub(r'(\b)(on\S+)=|(on\S+\s*([! ])\s*)=','', text)
         return self._incomplete_tags_re.sub("<\\1", text)
 
     def _encode_backslash_escapes(self, text):