nsIDOMNSHTMLDocument
te since gecko 14.0 domstring getselection(); nsidomdocument open(in acstring acontenttype, in boolean areplace); boolean querycommandenabled(in domstring commandid); boolean querycommandindeterm(in domstring commandid); boolean querycommandstate(in domstring commandid); boolean querycommandsupported(in domstring commandid); domstring querycommandtext(in domstring commandid); obsolete since gecko 14.0 domstring querycommandvalue(in domstring commandid); void releaseevents(in long eventflags); void routeevent(in nsidomevent evt); void write(); obsolete since gecko 2.0 void writeln(); obsolete since gecko 2.0 attributes attribute type description alinkcolor domstring ...
... querycommandtext() obsolete since gecko 14.0 (firefox 14.0 / thunderbird 14.0 / seamonkey 2.11) this method never did anything but throw an exception, and was removed entirely in gecko 14.0 (firefox 14.0 / thunderbird 14.0 / seamonkey 2.11).
... domstring querycommandtext( in domstring commandid ); parameters commandid the name of the command to query.

Document - Web APIs
document.querycommandtext()obsolete since gecko 14 this method never did anything but throw an exception, and was removed in gecko 14 (firefox 14 / thunderbird 14 / seamonkey 2.11).