scinote-web/app/views/reports/new/modal/_step_contents.html.erb

<%= bootstrap_form_tag remote: true, url: step_contents_project_reports_path(project, format: :json), method: :post, html: { id: "add-contents-form" } do |f| %>
  <%= hidden_field_tag :id, step.id %>

  <%= render partial: "reports/new/modal/step_contents_inner.html.erb", locals: { form: f, step: step } %>
<% end %>

<script type="javascript">
  $(function() {
    var form = $("#add-contents-form");
    var checkAll = form.find("#_step_content_all");
    var others = form.find("input:checkbox:not(#_step_content_all)");
    checkAll.click(function() {
      others.prop("checked", this.checked);
    });
    others.click(function() {
      checkAll.prop("checked", false);
    });
  });
</script>