Test how setCustomValidity reacts to too few arguments. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS b.setCustomValidity() threw exception TypeError: Failed to execute 'setCustomValidity' on 'HTMLButtonElement': 1 argument required, but only 0 present.. PASS fs.setCustomValidity() threw exception TypeError: Failed to execute 'setCustomValidity' on 'HTMLFieldSetElement': 1 argument required, but only 0 present.. PASS i.setCustomValidity() threw exception TypeError: Failed to execute 'setCustomValidity' on 'HTMLInputElement': 1 argument required, but only 0 present.. PASS k.setCustomValidity() threw exception TypeError: Failed to execute 'setCustomValidity' on 'HTMLKeygenElement': 1 argument required, but only 0 present.. PASS successfullyParsed is true TEST COMPLETE