Regular Expressions

• A regular expression is a text pattern.
• Regular expressions are of particular value for form field validation.
• Javascript has a RegExp object and related methods.
• Regular expressions use special characters to express text patterns
• Here is a web site offering a library of common text patterns including various countries' postal codes, phone numbers, dates, etc.

Peruse its source code. Observe:

• A regular expression tests for digits.
• The pattern match is sought with the test() method.

Lab

Your task:

• Copy the example and edit it as follows.
• Modify the text string pattern match to alert if it does not contain at least one non-alphabetic character (a digit or punctuation mark).

Solution

Don't peek unless you're stuck!

• Run it.
• Source code.

Extra for Experts

• Write the regular expression that validates a Schwab account number. These are of the form XXXX-XXXX where X is a digit and the hyphen is optional.
  • Answer

• Write the regular expression that validates a simplified phone number. These are of the form (XXX) XXXX-XXXX where X is a digit, the area code is optional, and the parentheses, space, and hyphen are optional.
  • Answer