JSP CUSTOM TAG LIBRARIES
Specifies that the formatting of the value supplied by the user in the specified input field must match the specified pattern. If validation fails, the body of this tag is evaluated.
Be sure the clientvalidate attribute of the input tag you are validating does not equal "none." The clientvalidate attribute of the form tag containing the input tag should be set to "true."
Contexts
Valid in:
alert
2) msgkey attribute value
3) message attribute value
4) body of this tag
HTML Attributes
See the Common HTML tag attributes section for definitions of the following standard HTML tag attributes:
style
Characters
Character classes
Standard POSIX character classes
Non-standard POSIX-sytle character classes
Predefined classes
Boundary matchers
Closures
All closure operators (+, *, ?, {m,n}) are greedy by default, meaning that they match as many elements of the string as possible without causing the overall match to fail. A reluctant closure matches as few elements of the string as possible when finding matches. If you want a closure to be reluctant, you can simply follow it with a '?'. {m,n} closures do not currently support reluctancy.
Logical operators
Backreferences
A "backreference" refers to the contents of a parenthesized expression within a regular expression. The first backreference in a regular expression is denoted by \1, the second by \2 and so on. The following expression will match any string in the form n=n (like 0=0 or 2=2):