Validation regular expression

All regular expressions are in PCRE format.

For web application form authentication, the regular expression must match a pattern on a page that is not accessible to an unauthenticated user. A good choice may be a "logout" link that is displayed only when the user has successfully authenticated. You can enter a maximum of 1024 characters.

No bounding delimiters are necessary, the entire string is considered the regex. This means that syntax like /foo/ or #foo# is not required. The / or # characters familiar in Perl or Python are needed for those languages to delimit the regex; we don't need those delimiters.

Only standard PCRE metacharacters need to be escaped:

\s -- space character

\w -- word character

\\ -- literal backslash Or escaping metacharacters to match a literal character

\. -- match a dot rather than anything

\? -- match a question mark rather than interpret it as a 0 or 1 quantifier Some more examples

Admin -- match the word Admin anywhere

.* -- match anything 0 or more times

a+ -- match the letter 'a' one or more times

successful\slogin -- match "successful login" separated by a space, tab, or new line

^response$ -- match the word response, with anchors to the beginning and end of the input

Note: The characters # and / are not acceptable in regular expressions.