What is a URL?

  1. The letters URL stand for Uniform Resource Locator.
  2. URLs are the exactlocation of specific bits of information on the Internet.
  3. Most URLs contain three parts:   the protocol, the hostname or server name and the directory or file name.

Diagram of a URL

 

  1. Protocol
    The means of communication your browser will use to get the file. If the browser is using HTTP to get to the file the protocol part is http.
    The protocol matches an information server that must be installed on the system for it to work. You cannot use an FTP URL on a machine that does not have an FTP server installed.

     

  2. Server Name
    The host name or server name is the Internet system on which the information is stored.

     

  3. Directory
    The location of the file or other form of information such as an image on the host.
    The directory can be an actual directory or folder and the actual name of the file.

 

Kinds of URLs

  1. HTTP
    Stand for Hypertext Transfer Protocol
    It is the most common type of URL since it is the protocol that the World Wide Web servers use to transfer information to browsers.
    Examples are:
    http://www.combustionlogic.com/index.com
    http://www.combustionlogic.com/lecture03/index.htm
    http://www.combustionlogic.com/images/linkdiagram.gif
    http://www.combustionlogic.com/lecture03/

     

    If the URL ends in a ( / )forward slash, the last part of the URL is considered a directory name. The file that you get using a URL of this type is the default file for that directory as defined by the HTTP server, usually a file called index.htm or html.

     

  2. HTTPS
    These are secure web pages.
    They are often used in commercial sites when dealing with the transfer of secure data such as credit card information.
    An example of https protocol:
    https://www.combusionlogic.com

     

  3. FTP
    Stands for File Transfer Protocol.
    Used to point to files located on FTP servers - usually anonymous FTP servers, that is ones that you can log in using anonymous as the login ID and your e-mail address as the password.
    Examples of FTP protocol are:
    ftp://ftp.foo.com/home
    ftp://ftp.foo.com/home/homepage.html
    The first URL retrieves a listing of all the files in the home directory. The second URL retrieves and parses the file homepage.html in the home directory.

     

  4. MAILTO
    The Mailto URL is used to send electronic mail.
    Some browsers do not support Mailto and produce an error link when a Mailto URL is selected.
    Here is an example:
    mailto:lorenwolf@hotmail.com
    Notice that the mailto URL takes only a colon (:) and there are no double forward slashes.

     



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