sS hjs_sendWindowVisibilityToWebSocket() {
  var isTabActive;
  
  function wsSendWindowVisibility() {
    console.log("isTabActive=" + isTabActive);
    if (wsReady) {
      console.log("Sending");
      ws.send(JSON.stringify({"isTabActive": isTabActive}));
    }
  }
  
  wsOnOpen(wsSendWindowVisibility);

  window.onfocus = function () { 
    isTabActive = true; 
    wsSendWindowVisibility();
  }; 

  window.onblur = function () { 
    isTabActive = false; 
    wsSendWindowVisibility();
  }; 
\