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The title says it all! In this video you're going to learn about what some languages do and how they work together. We'll start with a real world example to explain the client-server model, and then get into the languages used for front end (HTML, CSS, and JavaScript) and back end (PHP, Ruby, and Python) development.
To begin our journey about what common
languages do and how they work together,
0:00
let's begin by dissecting the languages
needed for a web application.
0:04
On second thought, let's begin at the
drive-through.
0:09
Imagine you're at a drive-through.
0:12
You order some food through one of those
giant intercom menus.
0:14
That order's sent to the kitchen where
they make the food.
0:18
When the food is ready, it's put into a
bag and handed to you through the window.
0:22
When you originally placed your order at
the intercom,
0:26
it was like typing a URL into the browser.
0:30
The URL is sent to a web server,
0:32
the kitchen, which then produces what you
asked for.
0:34
When the content is retrieved, aka your
food is ready, it's placed in a bag and
0:39
handed through the window, or the front
end of the website.
0:44
Just like a drive-through wouldn't put
just any order through the window when you
0:49
drive up, it's the same for a website.
0:53
This is called the client server model.
0:56
The client makes a request to the server.
0:58
And the server gives back the content to
the client.
1:02
Once the page has loaded,
1:05
from this point on when you send messages
through the front-end,
1:06
you are sending messages to the back-end,
which then returns what you asked for.
1:10
For example, maybe you forgot to ask for
ketchup, so
1:16
you ask the nice lady at the front for
some ketchup.
1:18
She turns around and asks the kitchen for
1:22
a packet of ketchup and hands it to you,
and you walk away happy.
1:23
You can see this when you go to the
Treehouse website.
1:28
When I pull up my Treehouse home page, I
only see my information.
1:31
Like the points I've accrued,
1:35
my name, and the course I'm on have all
come from the server.
1:37
But the layout and styling are going to
look the same, whether it's you or
1:42
anyone else signing on to the Treehouse
site.
1:46
The front end, or the drive-through window
if you will,
1:48
uses images in the languages HTML, CSS,
and JavaScript.
1:51
HTML and CSS are not programming languages
exactly.
1:57
HTML is a markup language which builds the
structure of the website.
2:01
And CSS is a styling language which tells
the browser how
2:05
to make that structure look.
2:09
Let's leave those languages aside for now.
2:11
You'll learn a lot more about them later.
2:14
The back-end, or
2:16
the kitchen in our analogy, is made of
what are called server-side languages.
2:17
And there are many different languages
like PHP, Ruby, Java, and
2:22
Python to choose from.
2:27
Whether you're programming for a website
or mobile app,
2:29
you're going to be dealing with a lot of
the same process you just saw for the Web.
2:32
One of the big differences when developing
mobile versus the Web is
2:37
the number of languages you'll need to
use.
2:42
If you're programming for a mobile android
device like the Moto 360 or
2:45
Samsung Galaxy,
2:49
you'll probably just be using Java to
program the whole application.
2:50
If you wanted to build something for a
mobile iOS device, like an iPhone or
2:55
an iPad, you'll be using Swift or
Objective-C.
3:00
Hopefully now you have a better grasp of
what back-end and
3:04
front-end languages are and how they work
together.
3:07
In the next video we'll talk about the
similarities and differences between some
3:11
of the back-end languages we discussed
like Ruby, Python, PHP, and Java.
3:16
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