forgeplus/app/views/admins/topic/cooperators/edit.js.erb

$("#cooperator-modals").html("<%= j render(partial: 'admins/topic/cooperators/form_modal', locals: {type: 'update'}) %>")
$(".cooperator-change-modal").modal('show');

$('.logo-item-left').on("change", 'input[type="file"]', function () {
  var $fileInput = $(this);
  var file = this.files[0];
  var imageType = /image.*/;
  if (file && file.type.match(imageType)) {
    var reader = new FileReader();
    reader.onload = function () {
      var $box = $fileInput.parent();
      $box.find('img').attr('src', reader.result).css('display', 'block');
      $box.addClass('has-img');
    };
    reader.readAsDataURL(file);
  } else {
  }
});