JavaScript Function

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JavaScript Function

What is function in JavaScript? A JavaScript function is a reusable block of code that performs a specific task. It allows you to encapsulate a set of instructions and run that set whenever needed. In detail, a JavaScript function is a named block of code that can take in inputs (arguments), perform actions, and optionally return a value.

What are the 3 types of functions in JavaScript?

1. Function declarations (named functions)
2. Function expressions (anonymous functions assigned to variables)
3. Arrow functions (shorter syntax for function expressions)

JavaScript Function Example

// JavaScript function example
function greet(name) { // JavaScript function declaration
  document.write("Hello, " + name + "!<br/>"); // Output message to the web page
  return true;
  }
  
// JavaScript function call
var result = greet("Reader");
document.write("greet function returned " + result);

FAQ (Interview Questions and Answers)

1. What is a JavaScript function?
   A reusable block of code designed to perform a specific task
   A keyword used to define a variable
   A data type in JavaScript
   
2. Which type of function in JavaScript is defined using the function keyword?
   Function declaration
   Function expression
   Arrow function
   
3. What is the purpose of an anonymous function in JavaScript?
   To assign a value to a variable
   To create a function without a specific name
   To perform mathematical calculations
   
4. Which type of function in JavaScript uses the arrow (=>) syntax?
   Function declaration
   Function expression
   Arrow function
   
5. What is the purpose of the return statement in a JavaScript function?
   To terminate the function execution
   To declare a variable
   To specify the value to be returned by the function
   

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