http://www.twinplanets.com"twinplanets.com" is the domain name. There are many specialized computers scattered all over the Internet whose only job is to look up domain names and convert them to IP addresses; these are called "domain name servers," or (rather redundantly) "DNS servers." If the domain name server for an institution crashes, the only way to access any Internet site from that institution is via its IP address until the domain name server is fixed.
C:\on a PC) for a site. Like a PC, you can have subdirectories beneath the root directory, and subdirectories beneath those, and so on. Eventually you end with an actual file name, such as
index.html. We call the entire string of file name preceded by subdirectories (and minus only the domain name itself) the path. For example, in the URL
http://www.twinplanets.com/tutorial/examples/index.htmlwe would call
twinplanets.comthe domain name and
/tutorial/examples/index.htmlthe path. Remember that you can also have a fragment (such as
#top) tacked on at the very end, enabling you to jump to an anchor somewhere in the document.
index.htmlat the location specified, and display it. If it can't find such a file, it may instead display a listing of the contents of the directory in question, and this is considered bad (you may not want the world to be able to see--and perhaps download--everything in the directory). A good rule of thumb is to make sure that every directory on your site has an
index.htmlfile present, even if it's just a file to redirect the user to another URL.
404 Page not founderror.
my file.htmland just had to keep the space in the filename, then every time you constructed a link to this file, you would write the filename in the URL like this:
|Terms to know from this lesson|
|IP address: A unique numeric identifier given to each and every computer on the World Wide Web. IP addresses consist of four numbers ranging from 0 to 255 separated by periods. "0.255.7.89" is an example of a valid IP address.|
|Domain name: A name that identifies one or more IP addresses. Domain names are used in Web URLs to identify a particular server that a Web page resides on. In the address
|Path: The part of a URL consisting of the file name preceded by the hierarchy of directory names in which the file is stored. The path tells the server what file the browser wants and where to find it. In the address |
|Unsafe or reserved characters: Characters which have a specific meaning or function within a URL, or which are not handled well by Web servers when included as part of a URL.|
|Character encoding: Encoding a character using a percent sign and a numeric value (actually the hexadecimal code for the character) instead of the character itself.|
This page last updated 2/5/2010.|