implement attr() content. Use mutation events to handle dynamic attr changes. Bug 214013, r=dbaron, sr=jst git-svn-id: svn://10.0.0.236/trunk@151885 18797224-902f-48f8-a5cc-f745e15eee43
implement attr() content. Use mutation events to handle dynamic attr changes. Bug 214013, r=dbaron, sr=jst git-svn-id: svn://10.0.0.236/trunk@151885 18797224-902f-48f8-a5cc-f745e15eee43