Validate an email input.
Use browser constraint validation for a required HTML email field.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Example</title>
</head>
<body>
<label for="email">Email</label><input id="email" type="email" required>
</body>
</html>Expected output EXAMPLE
Entering "invalid" makes the email field invalid. Replacing it with "ada@example.com" satisfies the browser's email-format check; this does not verify that the address exists.
Details
Save as example.html and open in a modern browser. Expected output describes the tested DOM behavior; the assertions below exercise the example in Chromium.
Browser validation does not replace server-side validation or verify mailbox ownership.
Tested on Ubuntu 24.04.5 LTS · · Chromium 141.0.7390.37 · libc6 2.39-0ubuntu8.9; Playwright 1.56.0
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged) / C.UTF-8
- Interpreter invocation
Chromium: open example.html; execute the published browser assertions- Container image ID
sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd- Code SHA-256
163ca9e8fbf00c082e0a72807c8abd556f46af48a299663c71c978ce2d741588- Dependencies
- libc6 2.39-0ubuntu8.9; Playwright 1.56.0
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
# No input files required.
Observed standard output
Expected output describes the rendered page. The standard-output record below is the browser test harness receipt; the additional assertions check the result and interactions.
Validate an email input: browser checks passed.
Exit code: 0. Standard error: empty. Validation: Shape/content assertions. System-dependent values above are one recorded run.
Additional assertions that passed
Checks recorded by the test harness. Where Python assertions are shown, browser cases use Playwright and simulator cases may inspect pin transitions: result.stdout is captured output, work is the temporary directory, and Path is pathlib.Path. The harness also imports json and csv.
await page.locator('#email').fill('invalid')
assert not await page.locator('#email').evaluate('(e) => e.checkValidity()')
await page.locator('#email').fill('ada@example.com')
assert await page.locator('#email').evaluate('(e) => e.checkValidity()')