text: CKEDITOR.dialog.add( 'checkbox_quizDialog', function( editor ) {
      return {
          title: 'Checkbox Quiz Properties',
          minWidth: 400,
          minHeight: 200,
          contents: [
              {
                  id: 'tab-basic',
                  label: 'Basic Settings',
                  elements: [
                      {
                          type: 'text',
                          id: 'question',
                          label: 'Question number',
                          validate: CKEDITOR.dialog.validate.notEmpty( "Question number field cannot be empty." )
                      },
                      // {
                      //     type: 'text',
                      //     id: 'opt_question',
                      //     label: 'Content option',
                      //     validate: CKEDITOR.dialog.validate.notEmpty( "Content option field cannot be empty." )
                      // },
                      {
                          type: 'text',
                          id: 'value_question',
                          label: 'Value option',
                          validate: CKEDITOR.dialog.validate.notEmpty( "Value option field cannot be empty." )
                      },
                      {
                          type: 'checkbox',
                          id: 'last_option',
                          label: 'Last option',
                          // 'default': 'checked',
                          // onClick: function() {
                          //     // this = CKEDITOR.ui.dialog.checkbox
                          //     alert( 'Checked: ' + this.getValue() );
                          // }
                      }
                  ]
              }
          ],
          onOk: function() {
              var dialog = this;
              var data_ques = $('.upload-page-custom').data('idquestion');
              console.log(data_ques);
              var class_quiz = dialog.getValueOf( 'tab-basic', 'question' );
              var value_quiz = dialog.getValueOf( 'tab-basic', 'value_question' );
              // var opt_quiz = dialog.getValueOf( 'tab-basic', 'opt_question' );
              var last_option = dialog.getValueOf('tab-basic', 'last_option' );
              var l_option = '';
              if (last_option) {
                  l_option = 'last-option';
                  var html = '<span class="label-checkbox key-label"><strong>' + value_quiz + '</strong></span> <input type="checkbox" class="question-quiz question-checkbox question-' + class_quiz + ' ' + l_option +'" name="question-' + class_quiz + '" value="' + value_quiz + '" onclick="bitest(this)" data-qnumber="' + data_ques +'"/> ';
                  data_ques++;
                  $('.upload-page-custom').data('idquestion', data_ques);
              }
              else {
                  var html = '<span class="label-checkbox key-label"><strong>' + value_quiz + '</strong></span> <input type="checkbox" class="question-quiz question-checkbox question-' + class_quiz + ' ' + l_option +'" name="question-' + class_quiz + '" value="' + value_quiz + '" onclick="bitest(this)" data-qnumber="' + data_ques +'"/> ';
              }
              editor.insertHtml( html );
          }
      };
  });