Client side
These files are copied to the users computers via web browser and displayed/run there.HTML
What's for:
Setting the basic site structure, like what part is text, what's a table, what's a picture, etc...
File extension:
.html
Code looks like:
<html>
<header>
<title>This is title</title>
</header>
<body>
Hello world
</body>
</html>
What's for:
Writing functions that run on the user's side, like get the local time, display alerts, set a timer, etc..
File extension:
.js
Code looks like:
function initCountdown() {
var oneDay = 24*60*60*1000; // hours*minutes*seconds*milliseconds
var today = new Date();
var secondDate = new Date(2017,7,27);
var diffDays = Math.round(Math.abs((today.getTime() - secondDate.getTime())/(oneDay)));
document.getElementById("countdown").text = diffDays;
alert(document.getElementById("countdown").text);
}
What's for:
Making the app pretty. Font type, color, size, image borders, alignment, some animations, background, etc...
File extension:
.css
Code looks like:
.on-the-day-section .two-column-holder ul li p {
padding: 0 2%;
font-family: "Lato", sans-serif;
font-size: 12.5px;
font-size: 1.25rem;
color: #828282;
text-align: center;
}
Server side
These files are executed privately on the web serverSQL
What's for:
Read and write from/to a database
File extension
.sql
Code looks like:
select first_name
, last_name
, phone
from customers
where name = 'Homer'
What's for:
Middle-man between users and database, depending on language it handles security, authentication, serving files, etc...
File extension:
Various (.php, .py, .java, .go, etc...)
Code looks like:
Various, but similar to the JavaScript example.
