RegEx fails on checking maximum length

Question

$regex = '/^(.+){,16}$/'

Nothing is matching, everything fails!

Answer 1

There are 2 problems:

1. {,16} matches the characters {,16} literally, you should use {0,16}
2. You have 2 quantifiers so instead of .+{,16} you should use .{0,16}

Regex that should work for you:

$regex = '/^.{0,16}$/'; // will match empty input also

RegEx Demo