What's the effect of adding 'return false' to a click event listener?

javascript html
Leonel picture Leonel · Sep 24, 2008 · Viewed 444.8k times · Source

Many times I've seen links like these in HTML pages:

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

What's the effect of the return false in there?

Also, I don't usually see that in buttons.

Is this specified anywhere? In some spec in w3.org?

Answer

Jim picture Jim · Sep 24, 2008

The return value of an event handler determines whether or not the default browser behaviour should take place as well. In the case of clicking on links, this would be following the link, but the difference is most noticeable in form submit handlers, where you can cancel a form submission if the user has made a mistake entering the information.

I don't believe there is a W3C specification for this. All the ancient JavaScript interfaces like this have been given the nickname "DOM 0", and are mostly unspecified. You may have some luck reading old Netscape 2 documentation.

The modern way of achieving this effect is to call event.preventDefault(), and this is specified in the DOM 2 Events specification.

Related questions

How do I check whether a checkbox is checked in jQuery?

I need to check the checked property of a checkbox and perform an action based on the checked property using jQuery. For example, if the age checkbox is checked, then I need to show a textbox to enter age, else …

Read More
How can I change an element's class with JavaScript?

How can I change the class of an HTML element in response to an onclick or any other events using JavaScript?

Read More
Which "href" value should I use for JavaScript links, "#" or "javascript:void(0)"?

The following are two methods of building a link that has the sole purpose of running JavaScript code. Which is better, in terms of functionality, page load speed, validation purposes, etc.? or function myJsFunc() { alert("myJsFunc"); } <a href="javascript:…

Read More