diff --git a/tools/distrib/check_copyright.py b/tools/distrib/check_copyright.py
index 19e227a805324f01692e0ad1588b137e2c3ddb4c..8a61626d15a460e8b1beae1417ec1f7a6e45eef5 100755
--- a/tools/distrib/check_copyright.py
+++ b/tools/distrib/check_copyright.py
@@ -56,6 +56,7 @@ LICENSE_FMT = {
   '.rb': '# %s',
   '.sh': '# %s',
   '.proto': '// %s',
+  '.js': ' * %s',
 }
 
 # pregenerate the actual text that we should have