callback.html

<script>
   function getQueryParams() {
    const params = {};
    window.location.search.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m, key, value) {
        params[key] = decodeURIComponent(value);
    });
    return params;
}

function doPost(url, data) {
    return new Promise((resolve, reject) => {
        const xhr = new XMLHttpRequest();
        xhr.open('POST', url);
        xhr.setRequestHeader('Content-Type', 'application/json');
        xhr.onload = () => {
            if (xhr.status === 200) {
                resolve(xhr.responseText);
            } else {
                reject(xhr.statusText);
            }
        };
        xhr.onerror = () => reject(xhr.statusText);
        xhr.send(JSON.stringify(data));
    });
}

const queryParams = getQueryParams();

doPost('https://github.com/login/oauth/access_token', {
    client_id: '89d97e38739c43a5d846',
    client_secret: '163e811519bf46aabe3bd9638342705350dd0c12',
    code: queryParams.code,
    redirect_uri: 'http://127.0.0.1:3000/'
}).then(response => {
    const accessToken = new URLSearchParams(response).get('access_token');
    document.cookie = `access_token=${accessToken}; path=/;`;
    window.location.href = '/'; // Redirect to homepage or another page
}).catch(error => {
    console.error('Error:', error);
});

</script>