How to fix Playwright "No frame for selector" and iframe locator issues?

Elements inside iframes are not reachable from top-level page.locator(...).

Use frameLocator() and wait for iframe content to render.

const checkout = page.frameLocator('iframe[title="Secure payment"]');
await checkout.getByLabel('Card number').fill('4242 4242 4242 4242');

If the iframe is cross-origin, avoid assumptions about direct DOM access.