In this column we discussed regular expressions and pattern matching, both in Perl and in JavaScript. Regular expressions are the cornerstone of any scipting language, as they provide a very powerful way to manipulate text. The form example demonstrates how regular expressions can be used to accomplish important tasks such as verifying the syntax of an e-mail. We also covered various ways to construct and execute regular expressions in JavaScript. After reading this column, you should know:

Pattern Matching and Regular Exressions

1. What you can do with regular expressions.
2. How to use various modifiers with matching operators.
3. How to construct regular expressions.
4. What rules apply to all regular expressions.
5. How to use values (backreferences) inside and after a regexp.
6. How to perform substitution commands.

JavaScript Regular Expressions

1. How to define regular expressions.
2. How to use the regular expression methods.
3. How to use backreferences.
4. How to create a general feedback form.
5. How to provide a workaround for older browsers.