URL format

When you try to access a webpage on the internet, the web address you put into the browser has a certain format. In its entirety (including the http:// part), this web address is known as a URL.

This tutorial focuses on:

URL definition and construction
Common protocols and their usage

URL definition and construction

URL stands for Uniform Resource Locator. A Uniform Resource Locator takes on a certain format through which you can create connections and/or access information using various protocols. A URL is the global address for a document or resource on the internet.

URL syntax:

protocol://domainOrIPAddress:port/path/filename

URL example:

http://www.landofcode.com/html/url-format.php

Parts of the URL explained:

protocol - Indicatates what protocol will be used to access the URL. Some common protocols include HTTP(Hyper Text Transfer Protocol) for transferring web content and FTP(File Transfer Protocol) for transferring files over a remote connection. The protocol is followed by ://
domain or IP address - Specifies an IP address or domain where the resource is located such as www.landofcode.com or 10.1.1.1
port - Specifies the port to use for the connection. It is usally omitted, as default ports are used for various protocols such as port 80 for HTTP.
path - Specifies a subdirectory at the server where the resource is located. If the path is omitted, then the root directory at the server is checked for the resource.
filename - The actual name of the resource. If the filename is omitted, then a default filename is used such as index.html for an HTTP connection.

Common protocols and their usage

Protocol	Usage
http	Access a file on the world wide web
https	Access a file on the world wide web through a secure connection
file	Access a file on the local computer
ftp	Access a file on an FTP server
gopher	Access a file on a gopher server
news	Access a Usenet newsgroup
telnet	Start a telnet connection
mailto	Create a link to an email message from a webpage
WAIS	Access a file on a WAIS server

HTTP

The URL type most internet users are used to. The standard HTTP webpage access URL.

Example of accessing a file on the world wide web:

http://www.landofcode.com/html/html-basics.php

HTTPS

Seen across online stores for data security reasons, the HTTPS protocol will secure data as its in transmission.

Example of accessing a file on the world wide web through a secure connection:

https://www.amazon.com

FTP

The FTP protocol is commonly used by webmasters to access the files on their webservers.

Example of accessing a file through ftp:

ftp://www.somesite.com/ftp/file.exe

Usenet News

The Usenet News contains many discussion groups you can subscribe to.

Example of accessing a Usenet newsgroup:

news:alt.binaries.dvds

Mailto

Mailto provides a link to an email message from a webpage

Example of creating a link to an email message from a webpage:

<a href="mailto:someone@yahoo.com">Contact Us!</a>

File

You can actually access your computer's file directory through a browser using File.

Example of accessing a file on the local hard drive:

file:///c:/windows/system/file.dll