// Индикатор загрузки в виде полоски
(function () { 

   // Css стиль для индикатора загрузки вкладок ....
   var uri = makeURI('data:text/css,'+ encodeURIComponent('\
      /* binding для добавления индикатора под "xul:label" каждой вкладки */\
      tabs.tabbrowser-tabs label.tab-text {\
         -moz-binding: url("data:application/xml,%3Cbindings%20id%3D%22tabprogressbarBindings%22%0A%09xmlns%3D%22http%3A%2F%2Fwww.mozilla.org%2Fxbl%22%0A%09xmlns%3Axul%3D%22http%3A%2F%2Fwww.mozilla.org%2Fkeymaster%2Fgatekeeper%2Fthere.is.only.xul%22%0A%09xmlns%3Axbl%3D%22http%3A%2F%2Fwww.mozilla.org%2Fxbl%22%3E%0A%3Cbinding%20id%3D%22tab-label%22%20extends%3D%22xul%3Ahbox%22%3E%0A%09%3Ccontent%3E%0A%09%09%3Cxul%3Avbox%20class%3D%22tab-label-inner-box%22%20flex%3D%221%22%3E%0A%09%09%09%3Cxul%3Astack%20xbl%3Ainherits%3D%22flex%22%20flex%3D%221%22%3E%0A%09%09%09%09%3Cxul%3Ahbox%20class%3D%22label-behind-box%22%20flex%3D%221%22%2F%3E%0A%09%09%09%09%3Cxul%3Avbox%20class%3D%22tab-progress-box%22%20flex%3D%221%22%3E%0A%09%09%09%09%09%3Cxul%3Aprogressmeter%0A%09%09%09%09%09%09class%3D%22tab-progress%22%0A%09%09%09%09%09%09mode%3D%22normal%22%0A%09%09%09%09%09%09xbl%3Ainherits%3D%22value%3Dtab-progress%22%2F%3E%0A%09%09%09%09%3C%2Fxul%3Avbox%3E%0A%09%09%09%09%3Cxul%3Ahbox%0A%09%09%09%09%09flex%3D%221%22%0A%09%09%09%09%09align%3D%22center%22%3E%0A%09%09%09%09%09%3Cxul%3Alabel%0A%09%09%09%09%09%09class%3D%22tab-real-text%22%0A%09%09%09%09%09%09flex%3D%221%22%0A%09%09%09%09%09%09xbl%3Ainherits%3D%22value%2Ccrop%2Caccesskey%22%2F%3E%0A%09%09%09%09%3C%2Fxul%3Ahbox%3E%0A%09%09%09%3C%2Fxul%3Astack%3E%0A%09%09%3C%2Fxul%3Avbox%3E%0A%09%3C%2Fcontent%3E%0A%3C%2Fbinding%3E%0A%3C%2Fbindings%3E#tab-label");\
      }\
      /* цвет, тень и фоновое изображение прогресса в base64 */\
      .tab-progress > .progress-remainder {\
         background-color: rgba(255, 255, 255, 0) !important;\
      }\
      .tab-progress > .progress-bar {\
         //box-shadow: 0 0 2px rgba(34, 153, 221, 0.26);\
         box-shadow: 0 0 2px rgba(255, 255, 255, 0);\
          background: #2299DD url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAACCAIAAAD5BB1nAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAYdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjAuNWWFMmUAAAAhSURBVEhLY1CaeXcUjaJRNIqGBBotsEbRKBpFQwTNvAsAqmb7PRUziHUAAAAASUVORK5CYII=") no-repeat right;\
      }\
      /* когда показывать, размеры, расположение */\
      .tabbrowser-tab[busy="true"]:not([progress="true"]) .tab-progress,\
      .tabbrowser-tab:not([busy="true"]) .tab-progress,\
      label.tab-text:not([tab-progress]) .tab-progress {\
         visibility: collapse;\
      }\
      .tab-progress,\
      .tab-real-text,\
      label.tab-text > .tab-label-inner-box,\
      label.tab-text > .tab-label-inner-box > *,\
      label.tab-text > .tab-label-inner-box > stack > *,\
      label.tab-text > .tab-label-inner-box > stack > * > spacer {\
         margin: 0 !important;\
         padding: 0 !important;\
         text-indent: 0 !important;\
      }\
      .tab-progress {\
         min-width: 0 !important;\
         height: 2px !important;\
         min-height: 2px !important;\
         max-height: 2px !important;\
         -moz-appearance: none !important;\
         border: none !important;\
         outline: none !important;\
         margin: 0 0 -4px !important;\
         position: relative !important;\
      }\
      .tab-progress > .progress-bar,\
      .tab-progress > .progress-remainder {\
         -moz-appearance: none !important;\
      }\
      .tab-progress-box { -moz-box-pack: end !important; }\
      \
      /* удалить стандартный индикатор загрузки( throbber ) */\
      .tab-throbber:not([pinned="true"]) { display: none !important; }\
      .tab-icon-image:not([pinned="true"]) { display: block !important; }\
      '));
   const sss = Cc["@mozilla.org/content/style-sheet-service;1"].getService(Ci.nsIStyleSheetService);
   sss.loadAndRegisterSheet(uri, sss.AGENT_SHEET); 
   addDestructor(function() sss.unregisterSheet(uri, sss.AGENT_SHEET) );

   
   // Отслеживать прогресс загрузки всех вкладок ....
   var tabsProgressListener = {      
          onProgressChange: function( browser, w, r, c, m, curProgr, maxProgr ) {
             if ( !maxProgr ) return;
         
             // добавлять атрибут с прогрессом загрузки к 'xul:label' каждой вкладки  
             var percentage = parseInt(curProgr * 100 / maxProgr);        
             var tab = gBrowser._getTabForBrowser( browser );
             var label = document.getAnonymousElementByAttribute( tab, 'class', 'tab-content').querySelector(".tab-text.tab-label");
             
             label.setAttribute('tab-progress', percentage );
          }        
   };
   gBrowser.addTabsProgressListener( tabsProgressListener );
   addDestructor(function() gBrowser.removeTabsProgressListener( tabsProgressListener ) );

})();