event.preventDefault vs return false

hyperlink.addEventListener('click', function (e) {
    // Don't redirect user to the link
    e.preventDefault();
});

submitButton.addEventListener('click', function (e) {
    // Don't submit the form when clicking a submit
    e.preventDefault();
});

#Differences

1. `return false` doesn't have any effect on the default behavior if you use the `addEventListener` method to handle an event. It only works when the event handler is declared as an element's attribute:
   hyperlink.addEventListener('click', function (e) {
       // Does NOT work
       return false;
   });
   
   // Work
   hyperlink.onclick = function (e) {
       return false;
   };

2. According to the HTML 5 specifications, `return false` will cancel the event except the `mouseover` event.

#Good practices

1. It's recommended to use the `preventDefault` method instead of `return false` inside an event handler. Because the latter only works with using the `onclick` attribute which will remove other handlers for the same event.
2. If you're using jQuery to manage the events, then you're able to use `return false` within the event handler:
   $(element).on('click', function (e) {
       return false;
   });

   Before returning the value of `false`, the handler would do something else. The problem is that if there's any runtime error occurring in the handler, we will not reach the `return false` statement at the end.
   In that case, the default behavior will be taken:
   $(element).on('click', function (e) {
       // Do something here, but if there's error at runtime
       // ...
       return false;
   });

   We can avoid this situation by using the `preventDefault` method before performing any custom handler:
   $(element).on('click', function (e) {
       e.preventDefault();
   
       // Do something here
       // The default behavior is prevented regardless errors at runtime
       // ...
   });

#Good to know

$(element).on('click', function (e) {
    // Prevent the deault event from happenning and
    // prevent the event from bubbling up to the parent element
    return false;
});

#See also

• event bubbling vs capturing
• stopImmediatePropagation vs stopPropagation