Export a Privacy-Safe Device Test Log as JSON, Entirely in the Browser

Support reports are easier to compare when they use the same fields. They are also safer when the form deliberately excludes secrets. This small browser-only page creates a local JSON file containing a device label, app name, network type, observation, and result. It has no server endpoint and sends nothing over the network.

The example is intended for ordinary troubleshooting notes. Do not add passwords, payment data, private playlist addresses, complete account identifiers, or authentication tokens.

<!doctype html>
<meta charset="utf-8">
<title>Local device test note</title>
<form id="note">
  <label>Device <input name="device" maxlength="80" required></label>
  <label>App <input name="app" maxlength="80" required></label>
  <label>Network
    <select name="network">
      <option>Wi-Fi</option>
      <option>Ethernet</option>
      <option>Other</option>
    </select>
  </label>
  <label>Observed result
    <textarea name="observed" maxlength="500" required></textarea>
  </label>
  <label>Test outcome
    <select name="outcome">
      <option>Passed</option>
      <option>Failed</option>
      <option>Inconclusive</option>
    </select>
  </label>
  <button>Download JSON</button>
</form>
<script>
document.querySelector('#note').addEventListener('submit', event => {
  event.preventDefault();
  const data = Object.fromEntries(new FormData(event.currentTarget));
  data.recordedAt = new Date().toISOString();

  const blob = new Blob([JSON.stringify(data, null, 2)], {
    type: 'application/json'
  });
  const url = URL.createObjectURL(blob);
  const link = Object.assign(document.createElement('a'), {
    href: url,
    download: 'device-test.json'
  });
  link.click();
  URL.revokeObjectURL(url);
});
</script>

Why keep the field list small?

Each field answers a practical comparison question. Did the same app fail on two devices? Did Wi-Fi and Ethernet behave differently? Was the second test recorded before or after an update? Free-form diagnostic dumps often include far more personal data than support needs.

What this page does not prove

A downloaded JSON record does not diagnose a cause. It only preserves what was observed under one set of conditions. Repeat a test after changing one variable, keep both files, and compare them. Do not change multiple network and app settings at once.

Safe extension ideas

You can add a software-version field, a controlled list of test steps, or a boolean indicating whether another app worked. Keep the form local. If you later add a server, review consent, retention, access control, and data minimization before transmitting anything.

The IPTV Harmony support information page uses the same principle: provide the smallest useful set of facts, without publishing private access details.

Technical references

• MDN Blob API
• MDN URL.createObjectURL()