What Does JavaScript:void(0) Mean?

If you have ever used JavaScript:void(0) in HTML or JavaScript code, and think about its purposes, then you are in the right place. In this blog, you will learn everything about the void(0) operator, understand its usage, and explore modern alternative methods that are similar to JavaScript:void(0).

Table of Contents:

• The void Operator in JavaScript
• The void(0) in JavaScript
• Use Cases of javascript:void(0)
• Alternatives to javascript:void(0)
  • Method 1: Using an event.preventDefault()
  • Method 2: Using return false
  • Method 3: Using Buttons for Actions
• Best Practices for javascript:void(0)
• Limitations of Using Void(0)
• Browser Support for javascript:void(0)
• Conclusion

The void Operator in JavaScript

The void operator in JavaScript returns undefined by evaluating an expression. The primary goal of the void is to ensure that an expression will return undefined no matter what the original expression evaluates.

Syntax:

void (1+2);

Here, (1+2) evaluates to 3, but it returns undefined because void is used before the expression, and void always returns undefined. You can check this by typing console.log(void 0) in the console. It will return undefined.

The void(0) in JavaScript

The void operator is a unary operator that evaluates an expression and returns undefined. When void(0) is used, it will evaluate the expression 0 and return undefined. This is commonly used in links (or hyperlinks) to prevent the default action of navigating to a new page.

Example 1: Link using JavaScript:void(0)

Output:

Explanation: In this example, you are using javascript:void(0) to stop the default behaviour of links. When you use the void(0), you are telling the browser to evaluate 0 and return undefined. Thus, clicking the link won’t navigate the user to another source or reload the page.

Launch Your Web Development Career

Start Learning Now

Explore Program

Use Cases of javascript:void(0)

Here is the list of some of the common use cases of JavaScript:void(0) in HTML and JavaScript:

• When you have a link that executes a JavaScript function, but you don’t want to navigate the user to the URL, then you can use javascript:void(0).
• During development, you may use javascript:void(0) as a placeholder in href attributes until the actual URL is available.
• You can use javascript:void(0) with event handlers onclick to execute JavaScript functions without causing navigation.

Alternatives to javascript:void(0) 

javascript:void(0) is still used, but there are some modern JavaScript practices that offer more readable and maintainable alternatives.

Method 1: Using an event.preventDefault()

The preventDefault() method is defined as a method that is used to prevent the default action of an event. It is mostly used in form handling in web development.

Syntax:

<a href="#" onclick="event.preventDefault(); alert('Link clicked!')">Click Me</a>

Example:

Output:

Explanation: In this example, the link is created by using the anchor tag (<a>). When you click it, the onclick event runs event.preventDefault(), which stops the browser from opening the link. Instead, an alert message appears on the screen. This is important when you want to send the form data to the server.

Method 2: Using return false

In case of inline event handlers, returning a false value from an event handler prevents the default action and stops the event from bubbling up to the DOM. But if you are using addEventListener, then this is not true. 

Syntax:

<a href="#" onclick="alert('Link clicked!'); return false;">Click Me</a>

Example:

Output:

Explanation: In this example, a hyperlink is created by using the <a> tag in HTML, but when you click it, the onclick event first shows an alert message. Then, the return false is executed. It stops the event from moving up to parent elements in the DOM (called event bubbling).

Explore the difference between event.preventDefault() and return false in JavaScript through this blog.

Method 3: Using Buttons for Actions

You can use a <button> element in HTML code instead of the <a> tag for some action. A button is used for taking actions, not navigation. Thus, you don’t need to prevent the default behavior like you do with a link.

Syntax:

<button onclick="alert('Button clicked!')">Click Me</button>

Best Practices for javascript:void(0)

Here are some of the best practices for using javascript:void(0) in the code:

• You can use the HTML elements like the <a> tag for navigation and the <button> element for performing some actions.
• Avoid using javascript:void(0), prefer using some modern methods like event.preventDefault() or return false because these methods have a more readable syntax.
• Write meaningful URLs in the href attribute because these URLs help in the process of search engine optimization.

Limitations of Using Void(0)

While javascript:void(0) is frequently used to prevent navigation or page reload, it comes with certain limitations and drawbacks. Let us discuss each limitation one by one:

• Writing javascript:void(0) directly in the href sometimes makes code unreadable, especially for beginners or when collaborating with other developers.
• Using javascript:void(0) in an href prevents search engines from identifying the link as meaningful content
• Modern coding standards do not allow the use of inline JavaScript in href or onclick attributes because of security and performance issues.

Browser Support for javascript:void(0)

The void operator and javascript:void(0) are used by many developers and are also supported by various browsers. Here is the list of browsers that support both:

• Google Chrome
• Mozilla Firefox
• Microsoft Edge
• Safari
• Opera
• Internet Explorer

Conclusion

So far, you learn about how to control the default behavior of hyperlinks in web development by using javascript:void(0). Besides this, you can also use an event.preventDefault() or return false to control hyperlinks. You can create efficient and user-friendly web applications by using appropriate JavaScript methods.

To learn more about JavaScript, check out this Web Development course and also explore JavaScript Interview Questions prepared by industry experts.

More Related Topics

• What is JavaScript?
• JavaScript Classes: Examples, Syntax, and Features
• Closures in JavaScript

What Does JavaScript:void(0) Mean – FAQs