Web servers are able to map the path component of a Uniform Resource Locator (URL) into:
For a static request the URL path specified by the client is relative to the web server's root directory.
Consider the following URL as it would be requested by a client over HTTP:
GET /path/file.html HTTP/1.1 Host: www.example.com
The web server on www.example.com will append the given path to the path of its root directory. On an Apache server, this is commonly /home/www (on Unix machines, usually /var/www). The result is the local file system resource:
The web server then reads the file, if it exists, and sends a response to the client's web browser. The response will describe the content of the file and contain the file itself or an error message will return saying that the file does not exist or is unavailable.