Tech Returners

Course Overview

• How Websites are made
• How to create your own Web Page
• Basic skills and tools that will useful for any coding you do
• The course aims to provide a basic overview of the technologies used, along with the tools and resources to discover more
• If you are ever in doubt
• Google it
• Check Stack Overflow
• Post on Slack
• Ask the person next to you
• Ask one of the TechReturners Training Team

What is a website?

A website is a collection of linked webpages (and their associated resources); a set of related files that is compatible to your browser.

• A web-page is just a file that your web browser is able to read and display, written in a markup language; HTML.
• HTML (HyperText Markup Language) is the most basic building block of the Web. It describes and defines the content of a webpage along with the basic layout of the webpage. Other technologies besides HTML are generally used to describe a web page's appearance/presentation (CSS) or functionality/ behavior (JavaScript).
• The website’s main webpage (or point of entry) is referred to as the homepage, or a landing page. This is predefined, and its document name must be set as index.html
• Because the web document files are sent to your browser, it is easy for you to look at them.
• There are no secrets in HTML, CSS or js. If there’s a part of a webpage that you like, it’s easy to find out how it is coded and use the technique yourself.

• http://www.bbc.co.uk/news

• https://techreturners.com/

How does the internet work?

• Computers connected to the Web are called clients and servers.
• The computers that hold web pages, sites and applications are called servers.
  Web servers are large, specialised computers that are (almost) permanently connected to the internet.
• The computers that allow people to access the web by providing software (browsers) for them to do so are called clients. They are the typical user’s Internet-connected device, for example - your laptop or mobile phone, connected to the internet through a browser.
• Servers respond to requests sent to them by clients. The Internet is the network layer that makes the Web possible, it lies on top of a very complex hardware infrastructure, which allows us to communicate by sending files to each other.

How does the Web work?

• How does the router know where to send your (client) requests?
  Many of our web interactions begin with a URL (uniform resource locator) being typed

• https://www.theguardian.com/uk

• https (Hyper Text Transfer Protocol Secure):
  the protocol or how to fetch the information (https for secured communication)
• www.theguardian.com : the host or where to fetch it from
• /uk : the path or precisely what information to fetch
• Example of http request (http://www.example.com/)
• When we type the URL into the address bar a request is sent over the internet and some information is returned to us.
• The protocol describes how the information is transmitted.
• The host describes where the information should come from and the path tells that location precisely what information to send.

IP Addresses

• Each computer on the internet has an address (an Internet Protocol address) so that requests can be sent to it and files returned - much like a telephone number.
• IP addresses are a sequence of numbers and ‘.’s such as 216.58.213.110
• Why don’t we just use IP addresses?
• As servers (computers which host and run the code for a website) are commonly switched, or run in parallel, or may be back-ups, IP addresses change often.
• IP addresses are also difficult and tedious to remember, so the internet works on a domain name system, that matches domain names such as google.com to IP addresses.

DNS (Domain Name Service)

• One of the first things that happens when you type a URL into your browser is a DNS lookup: your computer contacts a DNS server (Domain Name System server), which is basically a massive address book of IP addresses.
• The DNS server converts the domain name from the URL (e.g. google.com) into an address for a server (such as 213.123.245.98)
• Once the address of the web server has been found your request is forwarded onto it, the web server will interpret your request and send back one or more files.