What Does 'return false' Do in JavaScript Click Event Listeners?

The Impact of "return false" in Click Event Listeners

In web development, it's common to encounter links with an "onclick" attribute followed by a "return false;" statement:

<a href="#" onclick="someFunc(3.1415926); return false;">Click here !</a>

This intriguing syntax raises several questions:

Effect of "return false"

The primary effect of "return false" within a click event listener is to prevent the default browser behavior. In the case of links, this means inhibiting the browser from navigating to the target URL. Instead, the link triggers the specified JavaScript function, allowing custom actions to be executed.

Absence of "return false" in Buttons

Typically, "return false" is not used with button elements because they have their own built-in behaviors. When a button is clicked, it typically submits the form it is contained in or invokes the associated JavaScript function. Therefore, adding "return false" would not serve a discernible purpose.

Specification

Despite its widespread usage, the addition of "return false" to click event handlers is not explicitly specified in any official web standard. It is considered a legacy practice from the early days of DOM manipulation, where browser behaviors were not as clearly defined.

Modern Alternative

Today, the preferred method for preventing default browser behaviors is to call the "event.preventDefault()" method. This approach is standardized in the DOM 2 Events specification and provides a more consistent and explicit way to control event handling.

By understanding the impact of "return false" in click event listeners, developers can effectively prevent default browser behaviors and implement custom actions when specific links or elements are activated.

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