JAVASCRIPT

jquery option not disabled

const opt = $('#select option:not(:disabled)'); // array with all options not disabled
const first = $($('#select option:not(:disabled)')[0]); // first option not disabled

not disabled jquery

$(document).ready(function(){
  $(':checkbox.selectall').on('click', function(){
    $(':checkbox[class='+ $(this).data('checkbox-name') + ']:not(:disabled)').prop("checked", $(this).prop("checked"));
    $(':checkbox[class='+ $(this).data('checkbox-name') + ']:not(:disabled)').trigger("change");
  });
});