Declare document language and encoding.

Set the HTML language, UTF-8 encoding and viewport for accessible responsive content.

HTML example.html
<!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>
<h1>Café</h1>
</body>
</html>

Expected output EXAMPLE

The document uses English language metadata and UTF-8 encoding. The viewport follows the device width; these settings do not add visible page text.

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.

✓ Verified

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
51fc6e9ab3d66a8920a943868013c6c37910a3c1b0e4f9efad578aabeee88de1
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.

Declare document language and encoding: 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.

assert await page.locator('html').get_attribute('lang') == 'en'
assert await page.evaluate('document.characterSet') == 'UTF-8'
assert 'width=device-width' in await page.locator('meta[name=viewport]').get_attribute('content')