When the page loads WeBWorK starts the javascript timer and passes it the amount of time, so it shouldn't be hard to modify that value according to your desires.
The timer already triggers popup windows to tell students that they are almost out of time, so it should be possible to create a similar trigger to automatically click the "Next Page" button when time expires.
A couple of things to consider if you are trying this:
- You will need to give clear instructions to participants that they must choose an answer before time expires, since otherwise it will save a blank answer.
- The transition time from page to page may vary, so you will need to incorporate some margin of error in your value t.