The commissioning decision
A print studio asks whether a customer wants a proof posted out. The unchecked browser control is absent from the request, while the CRM keeps an old yes. Decide whether absence means no, unchanged or invalid for this particular preference. Do not let an integration choose that meaning accidentally.
Source and claim boundary
An unchecked checkbox contributes neither its name nor value to ordinary form submission. A checked checkbox without an explicit value uses on. MDN · Checked 16 October 2026.
Filled synthetic acceptance cases
Synthetic teaching data, not client records. Review the inputs and expected outcomes before running the isolated browser exercise. On narrow screens, scroll the table.
| Input | Check | Expected |
|---|---|---|
| postProof checked, value=yes | Browser payload | postProof=yes |
| postProof unchecked | Browser payload | No postProof key |
| postProof checked, no value | Browser payload | postProof=on |
How to verify beyond appearance
- Specify the meaning of absent, yes and invalid values in a small decision table.
- Run the three browser payload cases before applying any CRM defaults.
- Test the chosen absence policy against an existing test preference, then inspect the stored result.
Interpret the result
The fixture deliberately reports absence instead of inventing a universal no. A new enquiry may use a different contract from a partial account update. Record which operation was tested and whether stale values must be cleared. Marketing consent and legal acknowledgement require separate rules and evidence; a technical checkbox example cannot decide them.
What this does not prove
This is a non-sensitive delivery preference, not consent management, legal advice or proof of customer agreement.
Runnable fixture and handover record
Open the browser acceptance fixture · Read the test source。The fixture creates temporary elements with synthetic values inside the browser. It reads no account, uploads no file, and sends no email or form. Record the browser version, check name, observed value and pass state. Keep real integration evidence separate: a local pass is not a live delivery result.