The :placeholder-shown pseudo-class represents any <input> or <textarea> element that is displaying placeholder text.

With this rule, we can do this type of styling that would otherwise require the aid of JavaScript:

<input name="food" placeholder=" " />
<label for="food">Favorite food</label>

const input = document.querySelector('input');

input.addEventListener('focus', () => {
  // Add parent class to move label above input
});

input.addEventListener('blur', () => {
  // Check if input has value
  // Remove parent class to reset label
});

But instead of all this overhead, we can leverage the :focus and :placeholder-shown CSS rules:

input:focus + label,
input:not(:placeholder-shown) + label {
  top: 14px;
  left: 6px;
  font-size: 12px;
  color: #fff;
}

Here we check if the input has focus OR if it does not have the placeholder shown (meaning there is a text value). If either of these states apply, we have the label float to the top left.

A hell of a lot easier than JS event handlers! 😉

Here's a video using this in action:

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