What is this front end bullshit

custom.js

$(function() {
  dropzoneBody.ondrop = function(e) {
    e.stopPropagation();
    e.preventDefault();
    var self = this;
    self.className = 'dropzone'; // adds the border placeholder

    var file = e.dataTransfer.files[0];
    var reader = new FileReader();
    
    $("#loader").show();

    reader.onload = function(event) {
      var result = event.target.result;

      var lines = result.split('\n');
      setTimeout(function() {
        lines.forEach(function(perLine) {
          readData(perLine);
        });
        $("#loader").hide();
      }, 0);

    };

    reader.readAsText(file);
  };
});