nextElementSibling Test of nextElementSibling The result of this test is unknown. test(function() { var parentEl = document.getElementById("parentEl"); var fec = document.getElementById("first_element_child"); var nes = fec.nextElementSibling; assert_true(!!nes) assert_equals(nes.nodeType, 1) assert_equals(nes.getAttribute("id"), "last_element_child") })