Tornado websocket connection working with python client but fails with javascript client code

Question

In my project I have following websocket handler using tornado websockets:

class EchoWebSocket(tornado.websocket.WebSocketHandler):
def open(self):
    print("WebSocket opened")

def on_message(self, message):
    self.write_message(u"You said: " + message)
    # self.stream_logs()

def on_close(self):
    print("WebSocket closed")

I could connect to this websocket from an python client side code given here:

    import asyncio
    import websockets

    async def connect_to_websocket(uri):
        async with websockets.connect(uri) as websocket:
            await websocket.send("kdkdkd")
            while True:
                # Receive message from the WebSocket server
                message = await websocket.recv()
                print(f"Received message: {message}")
    
             
    
    async def main():
        uri = "ws://localhost:8889/myextension/echows"  # WebSocket server URI
        await connect_to_websocket(uri)

    if __name__ == "__main__":
        asyncio.create_task(main())

but when I try to connect it using javascript based client code it throws error VM449:3 WebSocket connection to 'ws://localhost:8889/myextension/echows/' failed javscript client code goes as:

async function connectToWebSocket(uri) {
      try {
        const connection = await new WebSocket(uri);

connection.onmessage = (event) => {
  console.log(`Received message: ${event.data}`);
};

connection.onerror = (error) => {
  console.error('WebSocket error:', error);
};

await connection.send("kdkdkd");

while (connection.readyState === WebSocket.OPEN) {
  // Receive messages and handle them appropriately (e.g., print or process)
  const message = await connection.receive();
  console.log(`Received message: ${message}`);
}
      } catch (error) {
console.error('Connection error:', error);
      }
    }

    const uri = "ws://localhost:8889/myextension/echows/"; 

    connectToWebSocket(uri);

I cannot figure out what am I doing wrong in js code although everything working while connecting using python.