A JS function to detect multiple tabs or new tabs in the browser for the same domain (Works for Chrome/Firefox/UC).

preventMultiTab.js

function preventMultiTab(){
  if(window.BroadcastChannel){
    var tab_sid = (new Date()).getTime();
    sessionStorage.setItem('tab_sid', tab_sid);
    var channel = new BroadcastChannel('tab-connections');
    channel.postMessage('ping:get_back_all_ids');
    channel.onmessage = function(e) {
      var message = e.data.split(':');
      if(message[0]=='close'){
        if(tab_sid > parseInt(message[1])){
          channel = null;
          console.log('New tab detected.');
        }
      }else if(message[0]=="ping"){
        channel.postMessage('close:'+tab_sid);
      }
    }
  }
}