WHMCS .htaccess Remove .php and .html - php

Question

Does anyone know how to specifically write an .htaccess file to remove .php from WHMCS client area, for example clientarea.php to clientarea. Also this will be needed to remove the .html extension from the knowledgebase articles as well.
I have tried this below but it is not working:
#Force non-.php:
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteRule ^([^\.]+)$ $1.php [NC,L]
Thank you for any help in advance!

Answer 1

This should work:
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^([^\.]+)/$ $1.php
HTML is the same story, change .php to .html so it would look like this.
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f
RewriteRule ^([^\.]+)/$ $1.html
To have them both, the .htaccess should look like this:
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^([^\.]+)/$ $1.php
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f
RewriteRule ^([^\.]+)/$ $1.html
Make sure to have mod_rewrite enabled ! If you do not have mod_rewrite enabled, this won't work.

Answer 2

Mod_Rewrite is compiled with Apache by default on cPanel.
Code:
root#server [~]# httpd -l|grep rewrite
mod_rewrite.c
You can enable it in cPanel for an account through the .htaccess file with a line such as:
RewriteEngine on
If you don't have cPanel I'm assuming the command would be some what the same but check if that doesn't work for you.