The web

Let’s talk about the web, and the internet.

We’ve all used the web: we’ve typed addresses into Firefox or Internet Explorer to get to a certain web page, and we’ve clicked links to go to other related web pages.

But how much do you know about what goes on behind the scenes? What really happens when you click a link or type in a page address?

There are actually a lot of things going on behind each of these small actions!

But the good news is, you don’t need to know all of it.

You only need to learn a little bit about how the web works to start making web pages.

Anything else you need, you can learn when you have a specific problem or idea.

Learning new things as you need them is a big part of being a developer. You don’t have to learn everything at once. :)

How the web works

In simple terms, the web works like this:

1. You ask your browser for a web page.
2. Your browser sends a request for that page to the appropriate computer on the internet.
3. The other computer sends the web page back.
4. Your browser receives the web page and displays it for you.

Let’s break that down in a little more detail.

1. You ask for a web page.

Normally, you type a web page address into your browser or click on a link (that contains an address) to ask for a web page.

A web page address is called a URL, which stands for Uniform Resource Locator.

A URL has three parts:

1. The protocol - the way that the web page should be sent. For web pages, this is usually http or https.
2. A host name - the name of the computer that has the page you asked for.
3. A path - the location of the page on the computer that has it.

2. Your browser asks another computer for that web page.

The parts of a URL give your browser all the information it needs to go and ask another computer for that page. We call computers that send web pages on request web servers.

Let’s look at the URL for the Muses Code JS Melbourne page, http://musescodejs.org/melbourne.html, as an example.

In this URL, the protocol is http, the host name is musescodejs.org, and the path is /melbourne.html. That means that the web server called musescodejs.org has sent us the melbourne.html file using the http protocol.

A protocol is an agreement on a set of rules. In this case it means the set of rules that describe how web page requests and responses should be packaged up and sent. http defines this, and https extends that protocol to handle security.

Look at the address bar of your browser right now, as you’re reading this page. Can you tell what the different parts are?

3. The other computer sends a web page back.

If the web server has the web page file that your browser asked for, it sends that file to your browser.

If the web server doesn’t have that file in the exact place you asked for, it will send an error page to your browser instead.

4. Your browser receives the web page and displays it for you.

Most web pages are written in a combination of the two languages we mentioned earlier: HTML and CSS.

Your browser reads the HTML and CSS in the web page, and then uses those rules to display the web page for you.

Pretty simple, right?

The case that we’ve gone through here is pretty simple: a server has a web page file, and sends it to you when you ask for it.

In reality, a web server might not actually have a file ready for every URL that it gets asked for.

Sometimes, web servers use other software to look at incoming browser requests and create the webpage on the fly for each specific request. However we aren’t going to build anything like that first. We are just going to build a few simple pages.

Let’s make it even simpler, just for now

In this workshop, we’re going to do something a little different.

Setting up a server can be complicated, but luckily for us browsers also support just opening up the file locally from your own computer. When you do this, the browser uses the file protocol. You’ll notice this in the URL when we get started.

The protocol is the only thing we’re going to change though. The underlying HTML and CSS will be exactly the same.

Ready? Let’s go!