preg_replace Info, execute, run and test online
Tue 06 Oct 2015 10:13:46 AM CEST - permalink - - http://preg_replace.onlinephpfunctions.com/

Regulex：JavaScript Regular Expression Visualizer.
Tue 06 Oct 2015 10:13:30 AM CEST - permalink - - https://jex.im/regulex/#!embed=false&flags=&re=%5E(a%7Cb)*%3F%24