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Chapter 20. The RegExp Object: Working w... > Regular Expressions: Regular Express...

Regular Expressions: Regular Expression Extensions

Regular expressions also support an “extension” syntax that uses parentheses with a question mark (these are not yet supported in the Netscape Navigator):

  • (?:pattern) Groups subexpressions as with ( and ), but doesn’t make submatches as ( and ) would.

  • (?=EXPR) Positive lookahead assertion; matches if EXPR would match next.

  • (?!EXPR) Negative lookahead assertion; matches if EXPR would match next.


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