inject modal to page through extension

1fetch(chrome.extension.getURL('/modal.html'))
2    .then(response => response.text())
3    .then(data => {
4        document.getElementById('inject-container').innerHTML = data;
5        // other code
6        // eg update injected elements,
7        // add event listeners or logic to connect to other parts of the app
8    }).catch(err => {
9        // handle error
10    });
11

1"web_accessible_resources": [
2    "modal.html",
3],
4