1 Test for a specific problem with previousSibling that failed in older versions of WebKit.
3 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
6 PASS walker.firstChild(); walker.currentNode.id is 'A1'
7 PASS walker.nextNode(); walker.currentNode.id is 'C1'
8 PASS walker.nextNode(); walker.currentNode.id is 'C2'
9 PASS walker.nextNode(); walker.currentNode.id is 'D1'
10 PASS walker.nextNode(); walker.currentNode.id is 'D2'
11 PASS walker.nextNode(); walker.currentNode.id is 'B2'
12 PASS walker.previousSibling(); walker.currentNode.id is 'C2'
13 PASS successfullyParsed is true