JSFiddle - React, Tailwind, and code Playground

by UNC00KED

HTML

<div id="dz" class="dropzoneDefault">
  <p>Drop files here to upload</p>
</div>

CSS

#dz {
  position: fixed;
  top: 2.5%;
  left: 2.5%;
  width: 95%;
  height: 95%;
  border: 2px dashed #9E9E9E;
  background-color: rgba(0, 0, 0, 0.5);
}

.dropzoneDefault {
  display: none;
}

.dropzoneOver {
  display: flex;
  justify-content: center;
  align-items: center;
  margin: auto;
}

JavaScript

window.addEventListener("dragenter", function(event) {

  event.preventDefault();

  document.getElementById("dz").className = "dropzoneOver";

});

window.addEventListener("dragleave", function(event) {

  event.preventDefault();

  document.getElementById("dz").className = "dropzoneDefault";

});