I personally use winXP and AppServ. I've got a "showitem.php" on my small website root. A good example usage: www.mydomain.com/showitem.php?id=123
I wish to use links like following:
Inshtaccess I write this line:
RewriteRule ^item/([^/]+)$ showitem.php?id=$1

Server directs to showitem.php and id is received effectively. However, primary issue is using the css and js files. Basically make "css/style.css" to "/css/style.css", page is proven on the web and but this is not on localhost, because root is "localhost" but files they are under "localhost/mydomain". I've also attempted "!-f" condition for .css files however it does not help also it can't so far as I realize. To resolve the issue, I ought to direct wrong css file interpretation towards the correct place, so I wish to redirect client request "item/css/style.css" to the original location "css/style.css". I add the next rules for localhost but can there be every other way?

RewriteRule ^item/css/([^/]+)$ /mydomain/css/$1
RewriteRule ^item/img/([^/]+)$ /mydomain/img/$1

Set basics tag inside your html mind.

<base href="http://www.mydomain.com/" />

After which set your stylesheet connecting pathways in accordance with the bottom, e.g.

<link href="css/style.css" />

you can write those to the file .htaccess

ErrorDocument 404 /error_404.php

/error_404.php is the error file you need to put something inside.