Javascript anonymous functions
The two most common ways to create a function in javascript are by using the function declaration or function operator . Anonymous functions are created using the function operator. Anonymous functions are used heavily in JavaScript for many things, most notably the many callbacks used by the language's many frameworks. The ECMAScript specification does not have any mention of the term anonymous. An anonymous function allows a programmer to create a function that has no name . In other words anonymous functions can be used to store a bit of functionality in a variable and pass that piece of functionality around it and created at runtime. Anonymous functions are declared using the function operator instead of the function declaration.Normal function definition:
function callMe() {
alert('Hello, I am normal function !!');
}
callMe();
In the above script you can see, it creates a function with name "callMe".
Anonymous function definition:
var callMe = function() {
alert('Hello, I am Anonymous !!');
}
callMe();
In the above script you can see, it declares an unnamed function and assigns it to a new variable named "callMe".
Here, we can see that these two ways of defining a function are essentially the same; both result in a function being created, and a new variable named "callMe" assigned to the current scope. However, the second function is anonymous. The function operator can be used anywhere that it's valid to use an expression. For example you can use the function operator when a variable is being assigned, when a parameter is being passed to a function or in a return statement.
Related Topics
- JavaScript Interview Questions (Part2)
- JavaScript Interview Questions (Part3)
- Is JavaScript a true OOP language?
- Advantages and Disadvantages of JavaScript
- Difference Between JavaScript and ECMAScript?
- What is noscript tag?
- Escaping Special Characters in JavaScript
- What is undefined x 1 in JavaScript?
- JavaScript : Logical Operators
- Difference between '=', '==' and '===' operators?
- How to reload a page using JavaScript?
- How to write html code dynamically using JavaScript?
- How to add html elements dynamically with JavaScript?
- How to load another html page from javascript?
- What Is The Disadvantages Using InnerHTML In JavaScript?
- What is Browser Object Model
- How to detect the OS on the client machine in JavaScript?
- Difference between window, document, and screen in Javascript?
- Difference between the substr() and substring() in JavaScript?
- How to replace all occurrences of a string in JavaScript?
- How to test a string as a literal and as an object ?
- What is Associative Array? How do we use it?
- What is the use of 'bind' method in JavaScript?
- Pure functions Vs. Impure functions in javascript
- Is Javascript a Functional Programming Language?
- What's the Difference Between Class and Prototypal Inheritance?
- Javascript, Pass by Value or Pass by Reference?
- How to prevent modification of an object in Javascript?
- What is 'this' keyword in JavaScript?
- How Does Function Hoisting Work in JavaScript?
- What do mean by NULL in Javascript?
- What does the delete operator do in JavaScript?
- What is the Infinity property used for in Javascript?
- Event bubbling and Event Capturing in JavScript?
- What is "strict mode" and how is it used in JavaScript?
- What is the difference between .call() and .apply()?
- Entire content of a JavaScript source file in a function block?
- What is an immediately-invoked function expression?
- What is escape & unescape String functions in JavaScript?
- What is the instanceof operator in JavaScript?
- What Are RESTful (REpresentational State Transfer)Web Services?
- What is Unobtrusive JavaScript & Why it's Important?
- What Does JavaScript Void(0) Mean?
- What are JavaScript Cookies?
- Difference between Client side JavaScript and Server side JavaScript
- TypeError: document.getelementbyid(...) is null
- Uncaught TypeError: Cannot read property of undefined In JavaScript
- What's the difference between Null and Undefined?