JavaScript Statements

A JavaScript program is a list of programming statements. Statements are executed one by one, in the same order as they are written.

Statements and Semicolons

JavaScript statements are separated by semicolons. While not strictly required (ASI handles most cases), using them is best practice.

Example

let a = 5;
let b = 6;
let c = a + b;
console.log(c);   // 11

Statements can be grouped together in code blocks, inside curly brackets {...}. Groups of statements are commonly found in functions.

Code Block in a Function

function calculate() {
    let x = 10;
    let y = 20;
    let sum = x + y;
    console.log("Sum:", sum);
}
calculate();

JavaScript ignores multiple spaces. Add spaces around operators for readability.

Readable Spacing

// These are equivalent:
let x=5+6;
let y = 5 + 6;   // much easier to read
console.log(x, y);

Keyword	Description
var	Declares a function-scoped variable
let	Declares a block-scoped variable
const	Declares a block-scoped constant
if	Executes a block conditionally
for	Marks a loop block
while	Marks a loop block
function	Declares a function
return	Exits a function and returns a value
switch	Marks a switch block

Exercise:

What are JavaScript statements typically separated by?

ColonsCommasSemicolonsPeriods