Regex Tester & Validator

This regex attempts to simulate a negative lookbehind in JavaScript, which historically lacked native lookbehind support prior to ES2018. It uses a negated character class to match exactly one character that is not a ?, :, ), ., {, 0, ,, or }. Following this initial character, it matches and captures the rest of the line into Group 1 using (.+). It is likely a malformed attempt at a boundary check, as the .{0,} sequence is incorrectly evaluated as literal characters inside the brackets rather than as a quantifier.