Communicating with two pages in the same domain but from different browsers/computers

I am trying to establish communication between two pages in the same domain. I want page B to send a message to everyone that has page A open. Websocket would be the best option, but the webhost does not allow it. I tried broadcast channel and window.postmessage, but none of those options seem to work. Is there a way that this could be done?

This is what I have on page B:

  <Button Id=TestButton onClick="swampmap();">Swamp</Button>  

  <script>
  function swampmap() {
                top.postMessage('Swamp', location.origin);
            }
  
   </script>

This is what I have on page A:

window.addEventListener( "message",
  function (e) {
        if(e.origin !== location.origin){ return; } 
        alert(e.data);
  },
  false);