What is the JavaScript void(0)?

The void operator evaluates the given expression and then returns undefined. If we pass $0$ as the unary expression operand to the void operator, JavaScript coerces $0$ to false and returns it undefined (which means “do nothing”).

This method of “doing nothing” becomes useful when we want to insert hyperlinks that perform useful functions on the page. Such hyperlinks allow a user to click on one and then perform a useful function, like updating a value on the webpage without loading a new page.

When to use Javascript void(0)

We can use Javascript void(0) when we do not want the browser to load a new page or refresh the same page​ when a link is clicked. Instead, we want the browser to perform the Javascript attached to that link.

Example

Click Here to display alert!

The link above is displayed using the code shown below:

Since it does not use void(0), clicking the link performs the intended function of displaying an alert, but it also reloads the page.

To prevent the page from performing the function and then reloading every time that this hyperlink is clicked, we need to modify our code slightly. In other words, we need to add javascript:void(0); to the href field in our hyperlink.

Click Here to display alert!

Once the hyperlink is clicked, javascript:void(0)​ tells the browser to “do nothing,​” hence preventing the browser from reloading the page while still performing the intended function.