Question 15-1.
What are the pros and cons of using JavaScript to validate form input?
Question 15-2.
Write the JavaScript code to display the warning "The username field must be at least six characters."
Question 15-3.
Write a regular expression to validate a U.S. zip code, including the optional "zip plus four" style.
Question 15-4.
Write the PHP code to test a variable called $zipcode using the regex expression from Question 15-3.
See the Appendix for the answers to these questions.