The validation succeeds only if the user input matches the pattern.Regular expressions let you check input text for a wide variety of custom conditions for which the input must follow a specific pattern.
Once you master the pattern language, most validation tasks become trivial.
You can concatenate simple regular expressions into complex search criteria to validate against complex patterns, such as any of several words with different endings.
You can use Cold Fusion variables and functions in regular expressions.
Everything that works in the normal character set also works here.
A word boundary matches the position where a word character is not followed or preceded by another word-character.(Not to be confused with Note: Java Script's regular expression engine defines a specific set of characters to be "word" characters.