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Arguments | Functions
Introduction to JavaScript
course content

Course Content

Introduction to JavaScript

Introduction to JavaScript

1. Basic Concepts
2. Variables and Data Types
3. Basic Operations
4. Conditional Statements
5. Loops
6. Functions

Arguments

Arguments are function variables that you can use only inside the function:

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function funcName(a, b) { console.log("Arg A =", a); console.log("Arg B =", b); }; funcName(15, 24); console.log(a); // This will raise an Error

Also, if you name the arguments the same as the variables outside the function, the function will use the arguments instead of the variables:

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let a = 15; function num(a) { console.log("(func) a =", a); }; num(20); console.log("(global) a =", a);

Note

When the function finishes execution, its space disappears, and all arguments lose their values.

Arguments are received sequentially:

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function numSet(a, b, c) { console.log([a ** 2, b + 2, c - 10]); }; numSet(15, 12, 99);

Unfilled arguments will receive the value undefined and will not be displayed in any way. Redundant arguments will not be used:

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function numSet(a, b, c) { console.log([a, b, c]); } numSet(12, 13); numSet(15, 12, 13, 15);

The function receives values as arguments. Variables outside the function remain unchanged. An argument is an independent value inside a function:

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let a = 15; function add(numb) { numb += 5; console.log("(func) numb =", numb); }; add(a); console.log("(global) a =", a);

Note

This does not work the same way for arrays because an array contains a reference to some data. This reference is passed to the function, so changes inside the function affect the data outside. This will be studied in the "OOP in JavaScript" course.

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Section 6. Chapter 4
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