2 <window xmlns=
"http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
3 xmlns:
nc=
"http://home.netscape.com/NC-rdf#"
4 title=
"insertBefore - Weirdness"
5 onload=
"var atab = document.createXULElement('tab'); atab.setAttribute('label','new'); let tabs = document.getElementById('tabs-id'); tabs.insertBefore(atab,tabs.allTabs[tabs.allTabs.length-1]);" >