Editing Courses/Essential HTML (section)

==URL==
URL stands for Uniform Resource Locator. It is the global address for documents on the Web.

It is trough URLs that from our computers we request webpages and these appear in our browsers.


A URL , such as: http://mouchette.org/home/chezmoi.html be decomposed in to the following parts:
* '''<nowiki>http</nowiki>''': the protocol
* '''<nowiki>mouchette.org</nowiki>''': the domain name 
* '''<nowiki>/home/chezmoi.html</nowiki>''': the file path

===Domain name===
The domain name, such as https://www.google.com/ is a kind of '''central address to a website.'''

It is via the domain name that the user sends a request to the computer (known as server) where the website lives, and as a reply a (html) file is sent back to the user's browser.

However this request and response journey is not so straight forward. That is because '''the domain name is not the true address, but an alias''' to the true address of the website.

The IP is the true address of a web page, or to be more precise, the address of the computer that hosts that website.  
As in the case of google.com its IP is 74.125.136.138

When a users types for a first time a URL on the browser, her request does not go straight to the computer that hosts that website.
Instead the request goes to a central list - DNS server - that has information about what url belongs to each address and sends back to the user's browser the IP corresponding to that URL. That way the user's browser gets to know where (wo which IP) to send its requests, when that URL is typed. 

In other words:
"[If you want]to access the Witness Web site you would type in the www.witness.org address, also known as a domain name, instead of 216.92.171.152. Your computer then sends a message with this name to a DNS server. After the DNS server translates the domain name into an IP address, it shares that information with your computer. This system makes Web browsing and other Internet applications more human-friendly for humans, and computer-friendly for computers."

[[File:DNS.png|700px]]

From http://en.flossmanuals.net/bypassing-censorship/ch006_chapter-1-how/

===file path===
The file path indicates the location of page inside the computer (aka server) that hosts this webpage.

In the URL http://mouchette.org/home/chezmoi.html it is indicated that the file we are requesting  is inside the "home" folder and it is called "chezmoi.html". 


[[File:folder_structure.svg|thumbnail|file paths]]


'''Exercise: '''
* Create an HTML file, that uses other local files (images, html files, etc), stored in parent, current and child folders. 
* Move the HTML file to a different directory
* Try to make all the local files are '''not broken'''  in HTML file