JavaScript events: .target vs .currentTarget

This seemingly comes up for me every six months or so, and I struggle to remember the whys of this. I just thought I’d share this little pointer as a reminder to myself, and hopefully it helps others.

Let’s say you have a clickable element, like a button, and you have some kind of inner element:

<button>
  <div>Inner Div</div>
</button>

(Why would this come up? Well, for me, I most often have to do this if I want to use flexbox inside of a button, as Firefox doesn’t like display: flex applied directly to a button. You have to insert an inner div and then get on with life. But I digress. Or you may have an SVG icon or image inside of a button.)

Let’s say you write an event handler like so:

const btn = document.querySelector('button');

btn.addEventListener('click', function(e) {
  console.log(e.target);
});

What do you think will happen?

You’ll get the div because, well, that’s what the user has in fact clicked on (even if the handler is written for the button:

> <div>Inner Div</div>

This is a problem if you’re expecting to do something based on the button – like a data attribute.

That is where currentTarget comes in.

const btn = document.querySelector('button');

btn.addEventListener('click', function(e) {
  console.log(e.currentTarget);  
});

// returns <button><div>Inner Div</div></button>

That will return you the element that is registering the click – in this case, the button.

So, the thing to keep in mind is that if you know that the source of an event doesn’t have children, you can use target. If you don’t know, or you already know that there are children, use currentTarget.

Read MoreLeave a comment

I’m retiring Ligatures.js

Just a quick post to let people know that I’m retiring ligatures.js – my little script that substituted in ligatures on web pages. I’m leaving it up for posterity, but I don’t recommend that people use it moving forward.

Why? I think it makes a lot more sense to use the text-rendering: optimizeLegibility; CSS declaration. It’s more future friendly, and avoids some of the pitfalls that my javascript solution presented. It’s not without it’s own issues – read more about it.

Read MoreLeave a comment