JavaScript functions are reusable blocks of code designed to perform a specific task. They help organize your program, reduce repetition, and make your code easier to read and maintain.

• A function is defined using the function keyword or arrow (=>) syntax.
• Functions accept parameters as input and return results using return.
• Functions run only when they are called (invoked) in your code.

JavaScript Function Examples

The following JavaScript section contains a wide collection of JavaScript examples. Many of these programming examples contain multiple approaches to solve the problem.

• Write a function
• Currying function
• Calling a JavaScript function in HTML
• setTimeout() function
• Anonymous functions
• Check whether a number is NaN or finite
• Encode and decode a URL
• Declare the optional function parameters
• Dynamic JavaScript function parameters.
• Importing one JavaScript file into another
• Overriding a JavaScript function
• Using function declaration
• Difference between call and apply
• Caller function
• Negating a predicate function
• Iterate over a callback n times
• Call a function with preset arguments
• Removing specific keys from an object
• Calling multiple functions with the same arguments
• Calling a function by its name as a string
• Measure time taken by a function to execute
• Check a function is defined
• Call a function with modified arguments
• Wait for a promise before returning a value
• Change a global variable inside a function
• Getting the index of the fastest function in an array
• Add an element horizontally in Html page
• Adding fade-out effect
• Add fade-in effect
• Understanding setTimeout() code snippets

For More details follow these articles :

• JavaScript Function Complete Reference
• JavaScript Examples
• JavaScript Tutorial