web-extension-starter/source/scripts/popup.js

import browser from 'webextension-polyfill';

function openWebPage(url) {
    return browser.tabs.create({ url });
}

document.addEventListener('DOMContentLoaded', async () => {
    const tabs = await browser.tabs.query({
        active: true,
        lastFocusedWindow: true,
    });

    const url = tabs.length && tabs[0].url;

    const response = await browser.runtime.sendMessage({
        msg: 'hello',
        url,
    });

    // eslint-disable-next-line no-console
    console.log(response);

    document.getElementById('github__button').addEventListener('click', () => {
        return openWebPage('https://github.com/abhijithvijayan/web-extension-starter');
    });

    document.getElementById('donate__button').addEventListener('click', () => {
        return openWebPage('https://www.buymeacoffee.com/abhijithvijayan');
    });

    document.getElementById('options__button').addEventListener('click', () => {
        return openWebPage('options.html');
    });
});