Before we start learning to build websites, it would be beneficial to briefly explore (a simplified version of) what goes on 'under the hood' when you enter a URL into your browser's address bar. For the purposes of this example we will use a page that should be familiar to most: the Google Homepage (

You are probably used to thinking of websites and pages as existing somewhere 'in the cloud' or on the internet, the very name web browser suggests something that allows us to look through the world wide web as a thing that exists somewhere else.

In reality, the web is actually just a collection of computers that store resources1 for other computers to access. For us to view a webpage, our browser must first download a copy from the computer on which it is being stored; and to do that, it must have a way of uniquely identifying the particular page it needs, along with the computer that is storing it. These unique addresses are called URLs.


URL stands for Uniform Resource Locator, and each is divided into 3 main parts: the protocol, which is the first part of the url up until the :// (in this case https); the domain name, which is the central portion of the url (in this case; and finally the path, which is the last part of the url from the forward slash onwards / (here only a single forward slash as we are accessing the website homepage). Your browser may hide the protocol (and path if it is the homepage) when a page is displayed in its address bar, but they are still there and will be visible if you copy and paste the url somewhere else.

Illustration of domain breakdown.
Url breakdown of Protocol = https, domain name =, and path = /.


The protocol is the method in which the browser accesses the resource, think of it a little like the various ways you could send a message to someone, such as writing a letter, calling them on the phone, or sending them a text message etc. For the purposes of building websites we don't need to understand how these work in-depth, just that http is the primary protocol used by the web, and that https is its more secure cousin.

Domain names

The domain name is the unique identifier of the particular website we are visiting. It is also the part of the URL that allows the browser to locate the computer on which the resource it is trying to access is being stored.

If we were to think of resources as items stored in a warehouse, the domain name would be the address of the warehouse itself. Domain names are actually split up into smaller chunks, but we don't need to cover that for now.


The path is the location of each individual resource within the domain. To reuse the analogy from earlier, if the domain name is the address to a warehouse, the path is the code for the slot on a shelf where the resource is stored.

As each URL must be unique, a domain could not have two resources with the same path; however, the same path on different domains would point to completely different resources (e.g. and are totally different pages on separate websites).

Requests and Responses

When you come to type a web address into your browser's address bar it must first make what is called a DNS lookup. This essentially involves consulting an online address book to find the IP address (a bit like a direct phone number) of the computer that stores resources for the domain name. In web parlance a computer that stores resources in this way is known as a server, and storing said resources is called hosting.

There are far too many websites out there for browsers to maintain their own address books of servers. Not only would they have to keep up to date with new ones being added, but also manage any changes of IP address where a website moves to a different server. Instead, they first consult the DNS directory to find the current IP address of the website you are requesting.

Using this address the browser then makes a request to the server hosting the website for the page that you want to view.

All being well, the server should respond to this request by sending the page back as a .html file. This .html file contains a description of the content of the page you wish to view and your browser uses this to render the page on your computer (displaying it on the screen for many users, but also reading it out for those who are blind or have a visual impairment).

Illustration of simplified request / response for web page. Icons from font-awesome.

To build websites, therefore, we need to create them in the format that browsers can understand: HTML.

Hyper-Text Markup Language

HTML stands for Hyper-Text Markup Language. Hyper-Text is essentially techno-geek speak for documents that link to other documents.

To return to the example of, when you make a search on google it scans the web for pages that might match the words you are looking for, and presents them as a list of links sorted by what it feels are the most relevant. Selecting any of these links will take you to that page so you can continue your search. It would probably not be exaggerating things much to say that links between documents are the single thing that contributes the most to the usefulness of the web.

To continue on with our breakdown of HTML you will notice that the L stands for language. In this case we are not referring to a language like English, Chinese, or Arabic, that is used by people to communicate with one another, but instead what is know as a computer language; which allows people to communicate with computers.

Fundamentally, computers deal in binary, familiar to most as long strings of 0s and 1s like this: 011000012. Having to use binary every time we want to tell a computer to do something would obviously become quickly tedious and error prone, so very clever people have invented a whole series of languages which are closer to those you would use in everyday life and which we can use to write instructions that the computer will then convert to binary before it follows them. There are a whole host of different computer languages for different use cases, and HTML is the one we use for describing webpages.

That, then, just leaves us with Markup. Markup describes the fact that HTML is a language for marking up documents; annotating parts of them to give them additional meaning. These annotations are what allow the browser to determine whether a particular part of the page is a piece of text or an image (along with a whole host of other possibilities) and serve as the instructions for how to build the page.

In the next chapter we will start to look at how html documents are formed.


  1. Anything that can be accessed on the web is classed as a resource, so not just pages, but also images; videos' pdfs etc.
  2. The number 01100001 is a binary representation of the lowercase letter a in the ASCII character set (a sort of code for representing letters with just binary numbers). As you can see, just typing out the word "Hello" would be very time consuming if we had to work in pure binary.