Wiki

Open terminal
cd to folder
Start php server php -S 127.0.0.1:8000
Open browser and enter http://localhost:8000/file-name.php

https://regexr.com

Regular expressions may have flags that affect the search.

There are only 6 of them in JavaScript:

i
With this flag the search is case-insensitive: no difference between A and a (see the example below).
g
With this flag the search looks for all matches, without it – only the first match is returned.
m
Multiline mode (covered in the chapter Multiline mode of anchors ^ $, flag "m").
s
Enables “dotall” mode, that allows a dot . to match newline character \n (covered in the chapter Character classes).
u
Enables full Unicode support. The flag enables correct processing of surrogate pairs. More about that in the chapter Unicode: flag "u" and class \p{...}.
y
“Sticky” mode: searching at the exact position in the text (covered in the chapter Sticky flag "y", searching at position)