Software

JavaScript Event.defaultPrevented


Whether you started with the old on_____ property or addEventListener, you know that events drive user experiences in modern JavaScript. If you’ve worked with events, you know that preventDefault() and stopPropagation() are frequently used to handle events. One thing you probably didn’t know: there’s a defaultPrevented proptery on events!

Consider the following block of code:

// Specific to a link
const link = document.querySelector('#my-link');
link.addEventListener('click', e => e.preventDefault());

// A larger document scope
document.addEventListener('click', documentClickHandler);
function documentClickHandler(event) {
    if (event.defaultPrevented) {// Using the property
        // Do one thing if the click has been handled
    }
    else {
        // Otherwise do something fresh
    }
}

When preventDefault is called on a given event, the defaultPrevented property gets toggled to true. Due to event propagation, the event bubbles upward with this defaultPrevented value.

I’ve been handling events for two decades and didn’t know this property existed until now. What’s great about defaultPrevented is that it stays with the event without needing to track track it globally!

  • Create Namespaced Classes with MooTools

    MooTools has always gotten a bit of grief for not inherently using and standardizing namespaced-based JavaScript classes like the Dojo Toolkit does.  Many developers create their classes as globals which is generally frowned up.  I mostly disagree with that stance, but each to their own.  In any event…

  • An Interview with Eric Meyer

    Your early CSS books were instrumental in pushing my love for front end technologies. What was it about CSS that you fell in love with and drove you to write about it? At first blush, it was the simplicity of it as compared to the table-and-spacer…

  • Use Elements as Background Images with -moz-element
  • Dijit’s TabContainer Layout:  Easy Tabbed Content


Source link
Show More

admin

Makes Noise is a blog where you can find all the juicy details on a variety of topics including health and fitness, technology, lifestyle, entertainment, love and relationships, beauty and makeup, sports and so much more. The blog is updated regularly to make sure you have all the latest and greatest information on the topics that matter most to you.

Related Articles

Leave a Reply

Your email address will not be published.

Back to top button