Creating regex for javascript

Question

I am keen on using both [^\u0000-\u007F]+ and ^[A-Za-z0-9._-](?:[A-Za-z0-9._ -]*[A-Za-z0-9._-])?$ as a one regex but it's so complicated, I just couldn't make it work? Any ideas how to integrate both?

I want to use JavaScript version for client-side verification and Php version for server-side verification.

Mind telling us what you intend to match instead of just the RegEx? — Joseph
– Joseph, Commented Sep 2, 2015 at 21:10
[^\u0000-\u007F]+ this is for non-english alphabetical characters such as àèéìòóùà and this ^[A-Za-z0-9._-](?:[A-Za-z0-9._ -]*[A-Za-z0-9._-])?$ is for only letters, numbers, dot, dash, underscore and no whitespaces on the beginning and end. — Rough
– Rough, Commented Sep 2, 2015 at 21:14
Your question is very unclear. Provide strings that should match and those that should not match. What you tried to achieve that and what went wrong. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Sep 2, 2015 at 21:24
in this case add them in the class instead of trying to find a range, probably this: ^[a-zàèéìòóùà0-9._-]+(?: [a-zàèéìòóùà0-9._-]+)*$ with a case insensitive flag (but your question stay very unclear). — Casimir et Hippolyte
– Casimir et Hippolyte, Commented Sep 2, 2015 at 21:45
@Rough: yes, the reason is that PHP regex does not support \uXXXX notation. However, there is a workaround. This ^[\u0080-\uFFFF\w.-](?:[\u0080-\uFFFF\w. -]*[\u0080-\uFFFF\w.-])?$ would match those letters. In JS, this regex can be used as is in literal notation. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Sep 2, 2015 at 22:07

Wiktor Stribiżew · Accepted Answer · 2015-09-03 09:20:30Z

2

I suggest using the remaining part of the Unicode table with [\u0080-\uFFFF] instead of [^\u0000-\u007F].

In JS, \w matches [A-Za-z0-9_], I suggest using

^[\u0080-\uFFFF\w.-](?:[\u0080-\uFFFF\w. -]*[\u0080-\uFFFF\w.-])?$

See demo

In PHP, just use \p{L} with /u modifier:

$re = '/^[\p{L}0-9_.-](?:[\p{L}0-9_. -]*[\p{L}0-9_.-])?$/u'; 
          ^^^^^           ^^^^^          ^^^^^           ^

It looks like no one likes \uXXXX in PHP. @nhahtdh confirms there may be issues with matching same code points.

edited Sep 3, 2015 at 9:20

answered Sep 2, 2015 at 22:14

Wiktor Stribiżew

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4 Comments

nhahtdh Over a year ago

Your recommendations for the first regex is terrible. If we want to match characters outside the ASCII range, you must always use u flag to correctly interpret the input. The solution with json_decode only happens to work, since the range encodes to UTF-8 is \xC2\x80-\xEF\xBF\xBF, which contains the range \x80-\xEF, which covers up to 3-byte UTF-8 encoded sequences. I think your answer should be edited to contain only the second solution.

nhahtdh Over a year ago

In PHP, if you want to specify character by code point, use \x{hh...h} syntax. It also works in character class, but the range is limited by the mode (in default mode, up to the size of the code unit - in PHP is 0xFF, in u mode, up to 0x10FFFF).

nhahtdh Over a year ago

\p{L} is a correct solution. json_decode on \u0080-\uFFFF is an unsafe solution without u flag - just use \x{hh...h} notation.

nhahtdh Over a year ago

Please don't try to make the same regex runs on both PHP and JS. There are fundamental differences in how they interpret the regex and the string representation in the two languages. Your idea only happens to work with this case - if the end points are different, the code may give you unwanted surprises.

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