Yesterday, a colleague asked me what we should do onfocusout on a task, we're working on. I told him it's called onblur in JavaScript (we were both right, more on this later!)

To this, another colleague said:

“Is this a reference to the band? Otherwise, it's a shitty name”.

(if you're not familiar with the band Blur or the onblur-event, this probably isn't funny at all)

… maybe it is a shitty name, but what if we could play Blur onblur?

First, we need to add an audio-file:

<audio src="woohoo.mp3" hidden id="woohoo"></audio>

We'll give it an id, woohoo, so we can easily reach it from code.

Then, we'll add a fieldset, with some inputs:

<fieldset id="app">
  <legend>Play Blur onblur</legend>
  <label>♪ Woohoo<input type="text" /></label>
  <label>♫ Woohoo<input type="text" /></label>
  <label>♫ Woohoo<input type="text" /></label>
</fieldset>

And finally, a little snippet of JavaScript, where we iterate the elements-collection of the fieldset, and add an onblur-eventListener to each input:

[...app.elements].forEach(input => input.addEventListener('blur', function(e) {
  woohoo.play()
}))

And that's it! Now focus on a field and leave it ;-)

Real use-cases

Okay, so admittedly this is just plain stupid, but maybe we could actually use this technique in conjunction with the Constraint validation API?

If a form-field is valid, it could play a tiny "ding!"-sound, and if it's invalid, a tiny "buzz"-sound.

focusout

Turns out my colleague was right: there is an event called focusout (and it's counter-part: onfocusin) – I'm just so old-school, that I've used focus and blur for ages!

Unlike blur, onfocusout actually bubbles up, meaning we can add a single event to the fieldset instead:

app.addEventListener('focusout', () => woohoo.play)

– but it's not funny at all to play Blur onfocusout, is it? 😂

In conslusion: Thank you to my colleagues for giving me an excuse to code something stupid and learning about the onfocusout-event!