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JavaScript Variables (`var`) Explained

The var keyword in JavaScript is an older way to create variables. It was commonly used in the past but is now considered a legacy practice.

Creating Variables with `var`

You create a variable by typing var, giving it a name, then assigning it a value:

var age = 30;         // storing a number
var name = "Bob";     // storing text
var isStudent = false; // storing true or false

Changing Values

With var, you can easily change the variable’s value later on:

var score = 50;
score = 75;             // updating the value
console.log(score);     // Outputs: 75

Why is `var` considered legacy?

Scope Issues: Variables declared with var are function-scoped or globally-scoped, causing unexpected behavior.
Hoisting: var declarations get "hoisted," potentially causing confusing bugs.
Modern JavaScript uses let and const, providing clearer and safer ways to handle variables.

Recommendation:

Use let or const instead of var for clearer, safer, and more predictable code.

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Understanding the Basic HTML Structure for JavaScript Integration

Variables with "const" and "let" keywords

Variables using the "var" keyword

A concise overview of JavaScript’s legacy var keyword—how to declare and update variables with it, why its function-scoped behavior and hoisting can lead to bugs, and why modern code prefers let and const for safer, more predictable variable handling.

2m 57s