PHP Regex doesn't work in JQuery

Question

I have following regex expression which is not working in JQuery but working fine in php version

What am I doing wrong?

Expression

if\s*\(((?:[^\(\)]|\((?1)\))*+)\)\s*{((?:[^{}]|{(?2)})*+)}

regex101 actually tells you which features are not supported in the JS regex engine. It's now about looking up how to do those in a different way, or if the syntax is different. — simbabque
– simbabque, Commented Mar 15, 2016 at 9:34
Invalid group, character '1' after '?' at column 23 as you can see if you input it into regen.io — MortenMoulder
– MortenMoulder, Commented Mar 15, 2016 at 9:54

Laurel · Accepted Answer · 2016-04-01 21:15:22Z

1

Regex is not a universal language. You are using some constructs only available in PHP/PCRE (see what I changed below) and not JavaScript.

This regex is about the same, working in either version: if\s*\(((?:[^\(\)]|\((\1)\))*)\)\s*{((?:[^{}]|{(\2)})*)}

What I changed

(?1) becomes (\1) (same with 2)

*+ becomes *

Note: I removed the backtracking control sequence: *+, so I wouldn't be surprised if this catastrophically backtracks with some inputs.

answered Apr 1, 2016 at 21:15

Laurel

6,23114 gold badges35 silver badges60 bronze badges

Sign up to request clarification or add additional context in comments.