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

316
CHAPTER 9 ■ PERFORMING FORM VALIDATION WITH REGULAR EXPRESSIONS
Drilling Down on the Basics of Pattern Modifiers
You may have noticed that the word regular in the title is not highlighted. This is because the previous
example is case sensitive.
To solve this problem with simple string replacement, you can opt to use the str_ireplace()
function, which is nearly identical to str_replace(), except that it is case insensitive.
With regular expressions, you will still use preg_replace(), but you’ll need a modifier to signify case
insensitivity. A modifier is a letter that follows the pattern delimiter, providing additional information to
the regex about how it should handle patterns. For case insensitivity, the modifier i should be applied.
Modify regex.php to use case-insensitive replacement functions by making the modifications shown
in bold:
Regular Expression Demo
em {
background-color: #FF0;
border-top: 1px solid #000;
border-bottom: 1px solid #000;
}