.htaccess file change url string not working on some pages - php

Question

I have updated my .htaccess file to remove the .php extension from the url strings. Code is here:
ErrorDocument 404 /lost.php
RewriteEngine On
RewriteBase /
# remove enter code here.php; use THE_REQUEST to prevent infinite loops
RewriteCond %{THE_REQUEST} ^GET\ (.*)\.php\ HTTP
RewriteRule (.*)\.php$ $1 [R=301]
# remove index
RewriteRule (.*)/index$ $1/ [R=301]
# remove slash if not directory
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} /$
RewriteRule (.*)/ $1 [R=301]
# add .php to access file, but don't redirect
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteCond %{REQUEST_URI} !/$
RewriteRule (.*) $1\.php [L]
Everything is working as it should do and the .php is being removed. Only problem is that when I try and access a certain area of the site (client area) the page is not displaying at all properly. Screen shot below:
Before adding the above code into the .htaccess file the url is:
www.mysite.co.uk/client-area.php
After adding the above code into the .htaccess file the url is:
www.mysite.co.uk/client-area/
and the page is not displayed at all correctly? Any idea why this is happening and what needs to be done to the .htaccess file code to fix this? Any help is welcome : )

Answer 1

Keep your .htaccess code like this:
ErrorDocument 404 /lost.php
RewriteEngine On
RewriteBase /
# remove enter code here.php; use THE_REQUEST to prevent infinite loops
RewriteCond %{REQUEST_METHOD} !POST
RewriteCond %{THE_REQUEST} \s/+(?:index)?(.*?)\.php[\s?] [NC]
RewriteRule ^ /%1 [R=301,L,NE]
# remove index
RewriteCond %{REQUEST_METHOD} !POST
RewriteRule (.*)/index$ $1/ [R=301,L,NE]
# remove slash if not directory
RewriteCond %{REQUEST_METHOD} !POST
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+?)/$ $1 [R=301,L,NE]
# add .php to access file, but don't redirect
RewriteCond %{DOCUMENT_ROOT}/$1\.php -f [NC]
RewriteRule ^(.+?)/?$ /$1.php [L]
For displaying css/js/images just use absolute path in your css, js, images files rather than a relative one. Which means you have to make sure path of these files start either with http:// or a slash /.
Alternatively you can try adding this in your page's HTML header: <base href="/" /> so that every relative URL is resolved from that URL and not the current URL.