JavaScript® Bible, Sixth Edition

Chapter 42. The Regular Expression and RegExp Objects

IN THIS CHAPTER

• What regular expressions are

• How to use regular expressions for text search-and-replace

• How to apply regular expressions to string object methods

Web programmers who have worked in Perl (and other web application programming languages) know the power of regular expressions for processing incoming data and formatting data for readability in an HTML page or for accurate storage in a server database. Any task that requires extensive search and replacement of text can greatly benefit from the flexibility and conciseness of regular expressions.

Most of the benefit of JavaScript regular expressions accrues to those who script their server-side programs on servers that support a JavaScript version that contains regular expressions. But that's not to exclude the client-side from application of this "language within a language." If your scripts perform client-side data validations or any other extensive text entry parsing, consider using regular expressions rather than cobbling together comparatively complex JavaScript functions to perform the same tasks.

Regular Expressions and Patterns

In several chapters earlier in this book, I describe expressions as any sequence of identifiers, keywords, and/or operators that evaluate to some value. A regular expression follows that description, but has much more power behind it. In essence, a regular expression uses a sequence of characters and symbols to define a pattern of text. Such ...