The concept of a function was formalized at the end of the 19th century in terms of set theory, and this greatly increased the possible applications of the concept. A function is often denoted by a letter …

What is a Function? A function relates an input to an output. It is like a machine that has an input and an output. And the output is related somehow to the input. " f (x) = ... " is the classic way of writing a …

Oct 6, 2025 · A function is a special relation or method connecting each member of set A to a unique member of set B via a defined relation. Set A is called the domain, and set B is called the co-domain …

Jun 14, 2024 · We also give a “working definition” of a function to help understand just what a function is. We introduce function notation and work several examples illustrating how it works.

Jan 13, 2026 · To use the language of set theory, a function relates an element x to an element f (x) in another set. The set of values of x is called the domain of the function, and the set of values of f (x) …

Jul 10, 2025 · In JavaScript, every function is actually a Function object. Creates a new Function object. Calling the constructor directly can create functions dynamically but suffers from security and similar …

Learn how functions can remember variables after the outer function finishes. Function Object Methods & Properties.