Getting Valid Input
In This Chapter
Extracting data from drop-down lists
Working with multiple-selection lists
Getting data from check boxes and radio groups
Validating input with regular expressions
Using character, boundary, and repetition operators
Using pattern memory
Getting input from the user is always nice, but sometimes users make mistakes. Whenever you can, you want to make the user's job easier and prevent certain kinds of mistakes.
Fortunately, you can take advantage of several tools designed exactly for that purpose. In this chapter, you discover two main strategies for improving user input: specialized input elements and pattern-matching. Together, these tools can help ensure that the data the user enters is useful and valid.
Getting Input from a Drop-Down List
The most obvious way to ensure that the user enters something valid is to supply him with valid choices. ...