Now at this point,
you know what the web is and how it works
and which key technologies are involved.
I, now, briefly wanna come back to this URL thing here,
the address which you enter in the browser,
and have a look at a couple of other technical details
of how the web works.
And then after that,
we're going to learn how you can get the most out
of the course before we, then, dive right into the code
and you'll learn how to build websites step-by-step.
So let's take another look
at this URL thing now, because there are a couple
of terms you must be aware of.
For example, we have this part at the beginning, here.
You don't enter this on your own very often.
Instead, it's added automatically by browsers.
This defines the so-called protocol that's used
for talking to the remote computer,
to the server. And here, HTTP or HTTPS is the standard.
And as a web developer,
you don't need to worry too much about this
because it is basically handled for you.
Still, that's this part.
Then, we have this thing in the middle.
This is the so-called Domain.
It's the human-readable address,
the identifier of a website. A human-readable
because domains like apple.com, amazon.com,
and so on, of course,
are pretty straight forward to memorize.
And I'll come back to this domain in a couple of seconds,
but this is all the part of every URL that you enter.
Now here, on this example slide, the last part, however,
is not part of every URL.
This is a so-called Path,
and you will often see this in URLs, as well.
Paths act as pointers to specific resources,
specific pages on a website. For example,
if you visit academind.com, which is our website,
if you just enter academind.com,
you end up on the starting page.
But if you, then, go to one of our sub pages,
like the tutorials page,
you see that the address changed.
It's now academind.com/tutorials,
and URL's support paths
because you can now grab the entire URL
that includes the path.
And you could share this with anyone in the world
and if another person enters this same URL
in their browser, they are directed to the same page
on the website, instead of always ending up
on the starting page.
That's why this is another important feature
of the web and of URLs.
You can point at specific resources on a website.
And, of course, in this course,
we're also going to build websites
that consist of multiple pages.
So that's the URL.
Now, I want to come back to this big picture
of how the web works
because here, we now also can dig a little bit deeper
to understand better what exactly happens under the hood
when you enter an address like academind.com
or amazon.com or any other address.
You enter this address,
and we learned that this is called a domain here
if you just have something like academind.com,
and this, then, in the end, leads to the browser
sending a request to some server,
which then sends back a response with the website code.
Now, what actually happens
is a slightly different thing though.
This request is sent,
but it's actually not sent with just this domain.
Instead, all the devices that take part in the Internet,
so to say, have so-called IP Addresses.
IP stands for Internet Protocol,
and it's another standard that controls how devices
in the internet are identified.
Now, IP addresses look something like this and therefore,
of course, they are pretty hard to memorize for humans,
but every device in the internet,
including your computer, has such IP address.
And these IP addresses are actually needed
for establishing connections and talking to each other.
Now, since they are hard to memorize,
we have these domains, though,
which are easier to memorize for humans,
but which are not used by default
to establishing these connections and sending requests.
And the reason for this is that,
all devices that are part of the internet need
such a unique identifier. But of course,
for example, your computer, if it's not hosting a website,
which it typically isn't,
doesn't have a human readable domain.
That's why we don't use domains
for establishing connections,
because every device has a IP address
but not every device has a domain.
However, as a user, as a visitor of a website,
we, of course, want to enter such a domain
to view the website, not the IP address.
Though, if you knew the IP address of a specific website,
you could enter this, as well.
But of course, typically, we don't know that.
That's why, as part of the Internet,
we have some special servers which are operated
by global organizations, the so-called DNS servers.
DNS stands for Domain Name System,
and these are servers that contain mapping tables,
you could say, long tables with all the known domains
and the IP addresses that belong to these domains,
so, the IP addresses off the remote computers
that host the websites that belong to certain domains.
And when you enter a address like amazon.com
in the browser, or academind.com or anything else,
your browser actually first talks to such a DNS server
to translate the domain into an IP address.
And then, once that IP address was returned,
then your browser sends the actual request
to this remote machine, to this server serving a website,
which is now identified with help of that IP address.
That's what actually happens here.
And even though that might sound like a long taking process,
this is actually all super quick and only takes a couple
of milliseconds, but that's what's going on
behind the scenes.
And that's all of the reason why,
when you want to publish a website,
you typically have to buy such a domain first,
at least, if you want to have a custom domain.
Because these domains have to be registered globally,
you can't just come up with one because, of course,
they must only be used once, they have to be unique,
and therefore, you wouldn't be able to, for example,
register amazon.com if you wanted to do that,
because that domain is already taken by the Amazon company.
But you can take other domains. And once you bought them,
they are registered and they are added
to these mapping tables, so to say.
And that's all that's important to understand
and to be aware of. We have these IP addresses,
which are actually used,
and domains, which are translated to these IP addresses.
Now as a last note, I did,
of course, say that every device
in the internet has such IP address,
but you don't need to worry that this means
that other people could start connecting to your computer.
This, by default, is not possible
because you can still control whether a device
is allowing incoming traffic or not.
And by default,
your computer does not allow incoming traffic.
These servers, which are serving websites,
are configured to allow incoming traffic.
Your computer typically is not,
so it has this IP, but it still isn't reachable
by everyone in the worldwide web.
And with that, we now had enough theory for the moment.
That's it, for the moment.
Let's now see how you can get the most out of this course
and how you can take this course before we,
then thereafter, dive into the actual code you can write,
and learn more about web development step-by-step,
from the ground up.