diff --git a/test/test_utils.py b/test/test_utils.py
index 0857c0fc0c..6ef498a666 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -814,6 +814,9 @@ class TestUtil(unittest.TestCase):
         inp = '''{"duration": "00:01:07"}'''
         self.assertEqual(js_to_json(inp), '''{"duration": "00:01:07"}''')
 
+        inp = '''{segments: [{"offset":-3.885780586188048e-16,"duration":39.75000000000001}]}'''
+        self.assertEqual(js_to_json(inp), '''{"segments": [{"offset":-3.885780586188048e-16,"duration":39.75000000000001}]}''')
+
     def test_js_to_json_edgecases(self):
         on = js_to_json("{abc_def:'1\\'\\\\2\\\\\\'3\"4'}")
         self.assertEqual(json.loads(on), {"abc_def": "1'\\2\\'3\"4"})
@@ -885,6 +888,9 @@ class TestUtil(unittest.TestCase):
         on = js_to_json('{/*comment\n*/42/*comment\n*/:/*comment\n*/42/*comment\n*/}')
         self.assertEqual(json.loads(on), {'42': 42})
 
+        on = js_to_json('{42:4.2e1}')
+        self.assertEqual(json.loads(on), {'42': 42.0})
+
     def test_extract_attributes(self):
         self.assertEqual(extract_attributes('<e x="y">'), {'x': 'y'})
         self.assertEqual(extract_attributes("<e x='y'>"), {'x': 'y'})
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 386897a856..2fe9cf585d 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -2267,7 +2267,7 @@ def js_to_json(code):
         "(?:[^"\\]*(?:\\\\|\\['"nurtbfx/\n]))*[^"\\]*"|
         '(?:[^'\\]*(?:\\\\|\\['"nurtbfx/\n]))*[^'\\]*'|
         {comment}|,(?={skip}[\]}}])|
-        [a-zA-Z_][.a-zA-Z_0-9]*|
+        (?:(?<![0-9])[eE]|[a-df-zA-DF-Z_])[.a-zA-Z_0-9]*|
         \b(?:0[xX][0-9a-fA-F]+|0+[0-7]+)(?:{skip}:)?|
         [0-9]+(?={skip}:)
         '''.format(comment=COMMENT_RE, skip=SKIP_RE), fix_kv, code)