How come some site urls do not include a file extension?

Question

I was browsing the internet and noticed, YouTube, for example, contains a URL like this to denote a video page: http://www.youtube.com/watch?v=gwS1tGLB0vc.

Answer 1

below it what I use in my .htaccess to make the url still run correctly without the HTML or PHP extension.

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f

means that if the file with the specified name in the browser doesn't matching with directory (-d) or files(-f) in your webserver, then rewrite rule below

RewriteRule ^(.*)$ $1.html

i'm not sure how the below work but I think that after it rewrite with html and if it still not matching it then rewrite with php

RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php

if it still not matching it will be show 404 page.

you also can redirect 404 with the code below in .htaccess

ErrorDocument 404 /404.html

importance is the code is working in for my site.

http://mintnet.net/services

http://php.mintnet.net/home

those doesn't need the file-extension.