code: function hideScrollbarUsingPseudoElement(el){
              var state = getState(el);
              var idName = 'vuebar-pseudo-element-styles';
              var selector = '.' + state.config.el2Class + '::-webkit-scrollbar';
              var styleElm = document.getElementById(idName);
              var sheet = null;
  
              if (styleElm) {
                  sheet = styleElm.sheet;
              } else {
                  styleElm = document.createElement('style');
                  styleElm.id = idName;
                  document.head.appendChild(styleElm);
                  sheet = styleElm.sheet;
              }
  
              // detect if there is a rule already added to the selector
              var ruleExists = false;
              for(var i=0, l=sheet.rules.length; i<l; i++){
                  var rule = sheet.rules[i];
                  if (rule.selectorText == selector) {
                      ruleExists = true;
                  }
              }
  
              // if there is rule added already then don't continue
              if ( ruleExists ) { return false }
  
              // insert rule
              // - we only need to use insertRule and don't need to use addRule at all
              //   because we're only targeting chrome & safari browsers
              if (sheet.insertRule) {
                  sheet.insertRule(selector + '{display:none}', 0);
              }
  
          }
docs: this is an experimental feature - it works only on chrome and safari - instead of hiding scrollbar by overflowing it with its parent set to overflow:hidden we hide scrollbar using pseudo-element selector ::-webkit-scrollbar