如何使用keyup函数删除div类？

Question

i want to ask you about keyup event listener, mine is not working. when i press the key, it adds pressed class to the div. but when i release the key it won't remove the class

 function keyPressed(e){ const key = document.querySelector(`.key[data-key="${e.keyCode}"]`); key.classList.add('pressed'); } function removePressed(e) { if(e.propertyName !== 'opacity') return; this.classList.remove('pressed'); } const keys = document.querySelectorAll('.key'); keys.forEach(key => key.addEventListener('keyup', removePressed)) window.addEventListener('keydown', keyPressed);

 .pressed { transform: scale(1.0); opacity: 0.7; }

 <div data-key="55" class="key item6"> <kbd>7</kbd> </div>

Answer 1

Try with

HTML:

<div data-key="55" class="key-item6">
      <kbd>7</kbd>        
    </div>

JS:

$('.key-item6').keyup(function () {
    if ($.trim($('.key-item6').val()).length) {         
        $(this).removeClass('pressed');
    }
});

Answer 2

It's hard to tell, but you can do some simple debugging. Change the following line of code:

  this.classList.remove('pressed');

To this:

  console.log(this.classList)

Here's how it should look:

function keyPressed(e){
  const key = document.querySelector(`.key[data-key="${e.keyCode}"]`);
  key.classList.add('pressed');
}
function removePressed(e) {
  if(e.propertyName !== 'opacity') return;
  console.log(this.classList)
}
const keys = document.querySelectorAll('.key');
keys.forEach(key => key.addEventListener('keyup', removePressed))
window.addEventListener('keydown', keyPressed);

If the console displays your element with the class you want to remove, you're on the right track!

Answer 3

The problem is with the event handler. You are attaching the event handler to key while that is not in focus. So your keyup event actually triggered on window .

If you really want to use keyup on the .key use tabindex and focus to the pressed element first. See the attached code.

 function keyPressed(e){ const key = document.querySelector(`.key[data-key="${e.keyCode}"]`); key.classList.add('pressed'); key.focus(); } function removePressed(e) { // if(e.propertyName !== 'opacity') return; this.classList.remove('pressed'); } const keys = document.querySelectorAll('.key'); keys.forEach(key => key.addEventListener('keyup', removePressed)) window.addEventListener('keydown', keyPressed); 

 .pressed { transform: scale(1.0); opacity: 0.7; } 

 <div data-key="55" class="key item6" tabindex=0> <kbd>7</kbd> </div> 

Also, e.propertyName is undefined causing it to return.

My suggestion is to bind keyup to window and use the same method as keyPressed to remove from classlist.