JS Tutorials
JS Introduction
JS Syntax
JS Comments
JS Variables
JS Operators
JS Data Types
JS Functions
JS Objects
JS Numbers
JS Arrays
JS Array Methods
JS Booleans
JS Events
JS Strings
JS Dates
JS Maths
JS Objects
Object Definition
Object Properties
Object Methods
Object Display
Object Prototypes
Object Iterables
Object Sets
Object Maps
Object References
JS Functions
Function Definition
Function Parameters
Function Invocation
Function Call
Function Apply
Function ClosuresJS Classes
Class Intro
Class Inhertitance
Class Static
JS Async
JS Callbacks
JS Aysnchronous
JS Promises
JS Sync/Await
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JavaScript Function Definitions
JavaScript functions are defined with the
function keyword.
You can use a function declaration or a function expression.
Function Declarations
Earlier in this tutorial, you learned that functions are declared with the following syntax:
// code to be executed
}
Declared functions are not executed immediately. They are "saved for later use", and will be executed later, when they are invoked (called upon).
Example
return a * b;
}
Semicolons are used to separate executable JavaScript statements.
Since a function declaration is not an executable statement, it is
not common to end it with a semicolon.
Function Expressions
A JavaScript function can also be defined using an expression.
A function expression can be stored in a variable: