Dropzone addClass

dropzone.html

<script>
var upload = document.querySelector('.upload');

upload.addEventListener("dragover", function( event ) {
  this.classList.add('dragging');
}, false);

upload.addEventListener("drop", function( event ) {
  this.classList.remove('dragging');
}, false);
</script>

<style>
.dragging {
  border:1px solid green;  
}
</style>

<div class="upload">
  <form action="">
    <input class="uploadfile" type="file" id="imageLoader" name="imageLoader">
    <div class="circle"><i class="flaticon-arrows-1"></i></div>
    <div class="text">Drag and Drop or browse from you computer</div>
  </form>
</div>