How to send JSON data to FastAPI using Javascript

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/daisyui/3.7.5/full.css" integrity="sha512-Lr5WBlKu2mm4qy5sAEaqC/61YBq2Yyxk8YdlgX+HMvIBSS4v+OP6BLf7d3lEF4lSUdiw0uZHLagpgOicVSMs4g==" crossorigin="anonymous" referrerpolicy="no-referrer" />

<div class="form">

    <input 
    id="username"
    type="text" 
    placeholder="usernme" 
    class="input input-bordered input-info w-full max-w-xs" />


    <input 
    id="password"
    type="password"
    placeholder="password"
    class="input input-bordered input-info w-full max-w-xs" />


    <button id="bt" class="btn btn-info">login</button>


</div>
<script type="text/javascript" src="https://code.jquery.com/jquery-3.6.3.min.js"></script>

<script>



    async function send_data(username, password) {
        fetch('/login', {

            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                'username': username.val(), 
                'password': password.val()
            })

            })
            .then(resp => resp.json()) // or, resp.text(), etc
            .then(data => {
                console.log(data); // handle response data
            })
            .catch(error => {
                console.error(error);
            });
        }


    let bt = $('#bt')

    bt.click(function () {
        let usernme = $('#username')
        let password = $('#password')
        send_data(usernme, password)
    })

</script>

<style>

    .form {
        display: flex;
        flex-direction: column;
        gap: 31px;
        width: 400px;
        padding: 20px;
        margin: 100px auto;
    }




</style>

from fastapi import FastAPI, Request
from fastapi.responses import HTMLResponse


app = FastAPI()


@app.get('/login')
def logIn():
    return HTMLResponse(open('login.html', 'r').read())

@app.post('/login')
async def login(request : Request):
    json = await request.json()
    return json