This test uses layoutTestController.overridePreference("WebKitUsesPageCachePreferenceKey", 1); to enable back-forward WebKit page cache for the duration of the test. The test enables cache, navigates to page-1, then to page-2 and then does history.back() to page-1. On navigation back to page-1, test verifies that previously-initialized timer continues to fire and onload is not called again. If test fails it hangs or outputs 'FAIL' below.

open page-1
page-1, about to navigate to page-2.
page-2, about to go back to page-1
Back on page-1, timer is still firing.
PASS.