html dom w3c dom html HTMLLegendElement htmllegendelementimpl htmlelementimpl htmllegendelement serialversionuid l getaccesskey accesskey accesskey accesskey accesskey.length accesskey accesskey.substring accesskey setaccesskey accesskey accesskey accesskey.length accesskey accesskey.substring accesskey getalign setalign align align htmllegendelementimpl htmldocumentimpl owner name owner name