Pro PHP and jQuery by Jason Lengstorf.pdf - Computer Science ...

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CHAPTER 9 ■ PERFORMING FORM VALIDATION WITH REGULAR EXPRESSIONS
Figure 9-4. A more complex replacement
■ Note The remaining examples in this section will use only regexes.
Matching Character Classes
In some cases, it’s desirable to match more than just a word. For instance, sometimes you want to verify
that only a certain range of characters was used (i.e., to make sure only numbers were supplied for a
phone number or that no special characters were used in a username field).
Regexes allow you to specify a character class, which is a set of characters enclosed in square
brackets. For instance, to match any character between the letter a and the letter c, you would use [a-c]
in your pattern.
You can modify regex.php to highlight any character from A-C. Additionally, you can move the
pattern into a variable and output it at the bottom of the sample data; this helps you see what pattern is
being used when the script is loaded. Add the code shown in bold to accomplish this:
Regular Expression Demo