sS hInitWebSocket(O... _) {
  optPar S wsVar = "ws";
  optPar S onOpen;
  optPar S onMessage;
  optPar S readyMsg = "WebSocket ready!";
  ret hreconnectingWebSockets()
    + hscript([[
      var wsReady = false;
      var wsInitialMsgs = [];
      var wsVerbose = false;
      var ]] + wsVar + [[ = new ReconnectingWebSocket(((window.location.protocol === "https:") ? "wss://" : "ws://") + window.location.host + "/");
      
      ]] + wsVar + [[.onopen = function(event) {
        wsReady = true;
        console.log(]] + jsQuote(readyMsg) + [[);
        wsInitialMsgs.forEach(function(msg) {
          if (wsVerbose) console.log("Sending initial msg: " + msg);
          ws.send(msg);
        });
        ]] + jsDropTrailingComments(onOpen) + [[ };
        
      ]] + wsVar + [[.onmessage = function(event) {
        ]] + unnull(onMessage) + [[
      };
      
      // add an initial message to send when websocket opens
      // also send it now if ws is open already
      function wsInitialMsg(msg) {
        wsInitialMsgs.push(msg);
        if (wsReady) {
          if (wsVerbose) console.log("Sending initial msg: " + msg);
          ws.send(msg);
        }
      }
    ]]);
}