code: function( command, param, force_selection )
          {
              // give selection to contenteditable element
              restoreSelection( node_wysiwyg, popup_saved_selection );
              // tried to avoid forcing focus(), but ... - https://github.com/wysiwygjs/wysiwyg.js/issues/51
              node_wysiwyg.focus();
              if( ! selectionInside(node_wysiwyg, force_selection) ) // returns 'selection inside editor'
                  return false;
  
              // for webkit, mozilla, opera
              if( window.getSelection )
              {
                  // Buggy, call within 'try/catch'
                  try {
                      if( document.queryCommandSupported && ! document.queryCommandSupported(command) )
                          return false;
                      return document.execCommand( command, false, param );
                  }
                  catch( e ) {
                  }
              }
              // for IE
              else if( document.selection )
              {
                  var sel = document.selection;
                  if( sel.type != 'None' )
                  {
                      var range = sel.createRange();
                      // Buggy, call within 'try/catch'
                      try {
                          if( ! range.queryCommandEnabled(command) )
                              return false;
                          return range.execCommand( command, false, param );
                      }
                      catch( e ) {
                      }
                  }
              }
              return false;
          }
docs: exec command https://developer.mozilla.org/en-US/docs/Web/API/document.execCommand http://www.quirksmode.org/dom/execCommand.html