The spellchecker shouldn't mark substrings of words after pasting. This test succeeds if only 'zz' is marked as misspelled. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". [object Text] moo zz PASS internals.markerCountForNode(currentNode, 'spelling') became 1 PASS internals.markerRangeForNode(currentNode, 'spelling', 0).toString() is "zz" [object HTMLBRElement] PASS internals.markerCountForNode(currentNode, 'spelling') became 0 [object Text] food. PASS internals.markerCountForNode(currentNode, 'spelling') became 0 PASS successfullyParsed is true TEST COMPLETE moo zz food.