diff --git a/youtube_dl/jsinterp.py b/youtube_dl/jsinterp.py
index a7440c582..9737f7002 100644
--- a/youtube_dl/jsinterp.py
+++ b/youtube_dl/jsinterp.py
@@ -232,7 +232,7 @@ class JSInterpreter(object):
     def extract_function(self, funcname):
         func_m = re.search(
             r'''(?x)
-                (?:function\s+%s|[{;,]%s\s*=\s*function|var\s+%s\s*=\s*function)\s*
+                (?:function\s+%s|[{;,]\s*%s\s*=\s*function|var\s+%s\s*=\s*function)\s*
                 \((?P<args>[^)]*)\)\s*
                 \{(?P<code>[^}]+)\}''' % (
                 re.escape(funcname), re.escape(funcname), re.escape(funcname)),