Reference

Tables worth keeping open in a tab. Every number here is generated from the standard rather than typed out, and every regex example is executed by the test suite — a reference that is quietly wrong is worse than none at all.

• ASCII tableThe complete ASCII table: all 128 codes in decimal, hex, octal and binary, with control-character meanings and HTML entity numbers.
• HTML entitiesA grouped list of HTML named entities with the character and code point for each: reserved characters, punctuation, symbols, arrows, Greek and accents.
• Regex cheatsheetJavaScript regular expression syntax on one page: character classes, quantifiers, anchors, groups, lookaround, escapes and every flag, with worked examples.