Give PDF forms an explicit submit button
An interactive PDF form should end in a real button wired to the submit-form action, so the user asks for the submission rather than tripping over it. W3C's own words are that the button exists to let users explicitly request a change of context, and that its intended job is to generate the request that sends the entered data. W3C publishes PDF15 as a sufficient technique when it is paired with actually providing that button as the way the form is submitted. The opposite of it has a name too. Submitting automatically when the last field takes a value is a documented failure in its own right, filed against the same rule. Acrobat Pro's form tools create the button and its action together.
How we find it in an audit
We complete the form with a keyboard and screen reader and check that changing or leaving any field never triggers submission on its own. Then we confirm a clearly labeled submit button exists, is reachable with Tab, and announces its purpose. Where the form is complex, we also open it in a tool that shows the field actions and read the button's action directly, which is faster than inferring it from behavior.
How affected users experience it
A form that submits when the final field loses focus takes the decision away from exactly the people who move through forms field by field. The screen reader user tabs onward to review their answers and the form has already gone. On an application or a payment instruction, unreviewed.
Passes vs. fails
Passes
The mandate ends in a button labeled "Submit mandate to bank" carrying the submit-form action. Nothing leaves the document until that button is activated.
Fails
A direct-debit mandate PDF fires its submit-form action when the account-number field loses focus. Tabbing away to double-check the sort code submits the mandate.
Other ways to satisfy this rule
8 guides on this site are filed under 3.2.2 On Input. W3C lists this one as sufficient for that rule only alongside G80, so the pair is what passes and neither half does on its own.
- G13sufficientSay what a control will do before it does it
- G80sufficientUse a submit button, not automatic submission
- H32sufficientGive every form a real submit button
- H84sufficientPair select menus with a real action button
- SCR19sufficientNever change context when a select changes
- F36failureDo not auto-submit when the last field changes
This guide is our interpretation of W3C technique PDF15: Providing submit buttons with the submit-form action in PDF forms. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.