TOPIC:

function handShake(str:string):string;
begin
 Result := TIdEncoderMIME.EncodeBytes( TIdHashSHA1.Create.HashString(str + '258EAFA5-E914-47DA-95CA-C5AB0DC85B11') );
end; 

procedure TForm1.IdTCPServer1Execute(AContext: TIdContext);
var
str:AnsiString;
Response: TStringList;
begin
 str:='';
 str:=Acontext.Connection.Socket.ReadLn;

 if str<>'' then form1.Memo1.Lines.Add(str);
 if pos('Sec-WebSocket-Key:',str)=1 then
      begin
        key:=handShake(copy(str,20,length(str)));
        form1.Edit1.text:=key;
      end;

  if pos('Sec-WebSocket-Extensions',str)=1 then
          begin

            form1.Memo2.Lines.Add('Key: '+key);
            Response := TStringList.Create;
            Response.Add('HTTP/1.1 101 Switching Protocols');
            response.Add('Upgrade: websocket');
            response.Add('Connection: Upgrade');
            response.Add('Sec-WebSocket-Accept: '+key);
            response.Add('Sec-WebSocket-Version: 13');

            form1.Memo1.Lines.Add('');
            Acontext.Connection.Socket.WriteLn(response.GetText);


            Response.Free;
          end;


end;

<script>
var socket = new WebSocket("ws://localhost:9999");
socket.onopen = function() {
  alert("Connected");
};
function mSend(){
socket.send('Hellow');
}
</script>
}