Matches all valid IP addresses from 0.0.0.0 to 255.255.255.255

Use this Regex for server-side validation also with some slight modifications like so for .NET -- @\w+([-+.']\w+)@\w+([-.]\w+)\.[a-zA-Z0-9]{2,6}(-.{2,6})*;

validates strings in time format HH:mm with hour in 24h format. only accepts up to 23:59

With regex you can count the number of matches. Can you make it return the number of uppercase consonants (B,C,D,F,..,X,Y,Z) in a given string? E.g.: it should return 3 with the text ABcDeFO!. Note: Only ASCII. We consider Y to be a consonant! Example: the regex /./g will return 3 when run against t...

See http://www.php.net/manual/en/reflectionparameter.tostring.php

Validate Gregorian calendar dates that contain 24-hour times. This will also correctly match the Feb 29 date when it falls on a valid leap year. Leap years occur every 4 years, with one exception: when a year is evenly divisible by 100 but not evenly divisible by 400, the year will not be a leap ye...

Validate and Capture (in 1000-2999 range) Leap-Year Correct

This regex replace the second tag content which has the prefix ":". If you want to replace the third, just increase the statement {1} to {2}, and so go on.

Finds a happy smile, except sad one

Break a URL into parts: protocol url path get parameters hash

trim leading and trailing whitespace from a string

Need Help, Matching Multiline Strings in Large Text File

improved "Ahmed Z" regexp. PHP date format (and input[type=text] format date too): YYYY-MM-DD. Year between [1900-2099]. No leap year check. Month 02 is limited to 29 days.