Jerad Rutnam Jerad Rutnam - 1 year ago 84
Javascript Question

Regex Match a character which is not followed by another specific character in javascript?

I'm writing a CodeMirror extension for Brackets. To defineSimpleCodeMode I need to do some pattern matching and I'm trying to figure out how to achieve $subject.



of all the html tags


And ignore html tags which are followed by

<% if %>

Note: I only want to get the starting
of it

If some can help me out it would be a great help. Please do let me know if you need anymore details.


Answer Source

While this seems to be a bad idea, I can see two ways of doing it :

1. Searching for < followed by anything but the % character, then ignoring it


The [^] sequence allows you to search for anything but the following character.

The (?:) sequence is for non capturing groups.

2. (Better, if supported) Searching for input not followed by % with a negative lookahead


The (?!) sequence succeeds if it doesn't match the following character, but is not captured.

If you also want to do it for %>, you can just "reverse" the first option :


Or you need a negative lookbehind :

(careful here, the lookahead won't work as you need to go backwards)


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