I have made a websocket with a server in a html page with java. I receive a json string an I need to get de data from the individual fields.

The code I use is this:

ws.onmessage = function (ev) {
      const obj = JSON.parse(ev.data);
          document.getElementById("COG").innerHTML = obj.COG;
          document.getElementById("AWA").innerHTML = obj.AWA;
          document.getElementById("demo").innerHTML = obj.Est Time en Route;
          document.getElementById("SOG-forward").innerHTML = obj.SOG-forward;

The first two are no problem but the second two are. It seems that it is not possible to have spaces or the "-" in the fieldname. I can not change that on the server side.

How can I get this working?