Stage ∞ Draft / June 6, 2026

Speccy - ECMAScript spec characters

A click-to-copy grid of the characters that ecmarkup’s formatter produces from HTML entities - the non-ASCII characters you use when writing Ecma spec text. Tracks ECMA-262, ECMA-402, ECMA-404, ECMA-424, ECMA-426, ECMA-427, ECMA-428. Built for tc39/ecma262#3882.

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Keystrokes for

Tap a glyph → copy the character (e.g. 𝔽). Tap the entity below it → copy the HTML entity (e.g. &Fopf;).

Chips show usage: 262·N = times used in ECMA-262; 402·N = times used in ECMA-402; 404·N = times used in ECMA-404; 424·N = times used in ECMA-424; 426·N = times used in ECMA-426; 427·N = times used in ECMA-427; 428·N = times used in ECMA-428. Start with By purpose for the common ones.

Derived from ecmarkup 24.1.0; the character union also covers 15.0.4, 16.2.0, 17.1.1, 18.4.0, 19.1.0, 20.0.0, 21.5.0, 22.0.0, 23.0.2, 24.1.0. 1430 characters total.

1 By purpose

The characters grouped by what they mean when writing spec text; the notational descriptions follow ECMA-262’s conventions. Every character that any tracked spec currently uses appears in a group here.

1.1 Numeric values and conversions

ECMA-262 distinguishes numeric kinds with subscripts: a value written with no subscript is a mathematical value, the subscript 𝔽 marks a Number, and ℤ marks a BigInt. The same letters name the operations that convert between those kinds.

1.2 Arithmetic

Operators and constants over mathematical values. These are the typographic forms - e.g. U+2212 MINUS SIGN, not the ASCII hyphen-minus.

1.3 Comparisons and relations

Relations between mathematical values. "=", "<", and ">" are written with their ASCII forms; the rest need typographic characters.

1.4 Sets and membership

Set-theoretic notation used when describing collections of values.

1.5 Lists and sequences

ECMA-262 List values use guillemet literal syntax: « 1, 2 » is a two-element List, and « » is the empty List.

1.6 Quotation and prose typography

Typographic punctuation for specification prose. Running emu-format turns straight quotes and double/triple hyphens into these forms.

1.7 Used in examples

Other characters that a tracked spec uses but that have no dedicated notation - letters and symbols appearing in examples such as case mapping, normalization, collation, locale data, and the IPA pronunciation of "JSON". Some have no HTML entity, so only the literal character is copyable.

2 Used in ECMA-262

The 28 characters that ECMA-262 currently uses, most frequent first.

3 Used in ECMA-402

The 27 characters that ECMA-402 currently uses, most frequent first.

4 Used in ECMA-404

The 4 characters that ECMA-404 currently uses, most frequent first.

5 Used in ECMA-424

The 7 characters that ECMA-424 currently uses, most frequent first.

6 Used in ECMA-426

The 14 characters that ECMA-426 currently uses, most frequent first.

7 Used in ECMA-427

The 2 characters that ECMA-427 currently uses, most frequent first.

8 Used in ECMA-428

The 2 characters that ECMA-428 currently uses, most frequent first.

9 All characters

Every character ecmarkup’s formatter can produce from an HTML entity, plus the few extra characters the tracked specs use, grouped by Unicode block.

9.1 Basic Latin (29)

9.2 Latin-1 Supplement (94)

9.3 Latin Extended-A (121)

9.4 Latin Extended-B (4)

9.5 IPA Extensions (3)

9.6 Spacing Modifier Letters (9)

9.7 Greek and Coptic (59)

9.8 Cyrillic (92)

9.9 General Punctuation (30)

9.10 Currency Symbols (1)

9.11 Letterlike Symbols (44)

9.12 Number Forms (12)

9.13 Arrows (77)

9.14 Mathematical Operators (231)

9.15 Miscellaneous Technical (38)

9.16 Control Pictures (1)

9.17 Enclosed Alphanumerics (1)

9.18 Box Drawing (40)

9.19 Block Elements (6)

9.20 Geometric Shapes (25)

9.21 Miscellaneous Symbols (13)

9.22 Dingbats (7)

9.23 Miscellaneous Mathematical Symbols-A (10)

9.24 Supplemental Arrows-A (8)

9.25 Supplemental Arrows-B (90)

9.26 Miscellaneous Mathematical Symbols-B (62)

9.27 Supplemental Mathematical Operators (182)

9.28 Miscellaneous Symbols and Arrows (2)

9.29 Alphabetic Presentation Forms (5)

9.30 Mathematical Alphanumeric Symbols (133)

9.31 Miscellaneous Symbols and Pictographs (1)