Reuse Code With Functions in JavaScript

JavaScript·1 min read·Jan 1, 2026

In JavaScript, a function is a reusable code structure that allows you to encapsulate a set of related statements in order to perform a specific task.

Functions allow you to easily reuse and execute these statements multiple times from various parts of a script, without having to manually repeat them.

💡 Note that executing, calling, running, and invoking a function essentially mean the same thing and are often used interchangeably.

Declare and execute functions

In JavaScript, functions are declared using the function keyword:

function functionName() {  statements}

Where:

  • functionName is the name of the function.

  • () are delimiters used to list function parameters.