This document introduces some basic concepts in JavaScript including variables, data types, flow control, and functions. Variables are used to store and retrieve values and are fundamental building blocks. JavaScript supports basic types like strings and numbers. Flow control allows executing code conditionally using if/else statements and loops. Functions help modularize and reuse code by defining pieces of code that can be called multiple times.

1. Variables & types
Flow
control
Functions
Javascript basics Andrea Tino
This document uses graphic assets from Freepik
var name = init-value ;
var name ;
Variables are used to store values
and retrieve them later. They are
essential building blocks in every
program you will ever write.
Javascript
supports very
basic types:
strings and
numbers.
var str = “hello”;
var integer = 10;
var decimal = 1.5;
var num1 = 1/2;
var num2 = num1*2;
var myvar = 0;
console.log(myvar);
code
if ( condition ) {
}
Javascript is a programming
language very simple but
extremely powerful. It is used
by browsers today so that web
pages can be interactive and
very dynamic.
In your favorite browser’s
window, hit F12 and bring up
the Developer Tools. You can
write some Javascript in the
console tab to have some fun.
Sometimes you ant certain code to be
executed, but not always.
Conditionals are used to execute
code only when one or more
conditions are met.
Loops (or cycles) are used everytime
you want to execute the same code
many times.
code
for (var i=0; i< n ; i++) {
}
if (1 < 2) {
alert(”Hi!”);
}
for (var i=0; i<10; i++) {
console.log(”This is:” + i);
}
What if you have a piece of code you
end up executing many times in
different parts of your code?
Functions help you modularize and
reuse pieces of code that you execute
very often in your program.
code
function name ( args ) {
}
A function must first be declared:
function-name ( args );
Then a function can be invoked:
function greetMe (name) {
alert(”Hello ” + name);
}
greetMe (”Batman”);