let xulElements = ["action","arrowscrollbox","assign","bbox","binding","bindings","box","broadcaster","broadcasterset","browser","button","caption","checkbox","colorpicker","column","columns","command","commandset","conditions","content","datepicker","deck","description","dialog","dialogheader","dropmarker","editor","Findbar","grid","grippy","groupbox","hbox","iframe","image","key","keyset","label","listbox","listcell","listcol","listcols","listhead","listheader","listitem","member","menu","menubar","menuitem","menulist","menupopup","menuseparator","notification","notificationbox","observes","page","panel","param","popup","popupset","preference","preferences","prefpane","prefwindow","progressmeter","query","queryset","radio","radiogroup","resizer","richlistbox","richlistitem","row","rows","rule","scale","script","scrollbar","scrollbox","scrollcorner","separator","spacer","spinbuttons","splitter","stack","statusbar","statusbarpanel","stringbundle","stringbundleset","tab","tabbox","tabbrowser","tabpanel","tabpanels","tabs","template","textbox","textnode","timepicker","titlebar","toolbar","toolbarbutton","toolbargrippy","toolbaritem","toolbarpalette","toolbarseparator","toolbarset","toolbarspacer","toolbarspring","toolbox","tooltip","tree","treecell","treechildren","treecol","treecols","treeitem","treerow","treeseparator","triple","vbox","where","window","wizard","wizardpage","thumb","toolbarpaletteitem","treecolpicker","spring","text","menubutton","popupgroup","slider","scrollbarbutton","contextmenu","context","linkset"];

let htmlElements = ["a", "abbr", "acronym", "address", "applet", "area", "article", "aside", "audio", "b", "base", "basefont", "bdi", "bdo", "bgsound", "big", "blockquote", "body", "br", "button", "canvas", "caption", "center", "cite", "code", "col", "colgroup", "data", "datalist", "dd", "del", "details", "dfn", "dialog", "dir", "div", "dl", "dt", "em", "embed", "fieldset", "figcaption", "figure", "font", "footer", "form", "frame", "frameset", "h1", "h2", "h3", "h4", "h5", "h6", "head", "header", "hgroup", "hr", "html", "i", "iframe", "image", "img", "input", "ins", "kbd", "keygen", "label", "legend", "li", "link", "listing", "main", "map", "mark", "marquee", "menu", "menuitem", "meta", "meter", "multicol", "nav", "nobr", "noembed", "noframes", "noscript", "object", "ol", "optgroup", "option", "output", "p", "param", "picture", "plaintext", "pre", "progress", "q", "rb", "rp", "rt", "rtc", "ruby", "s", "samp", "script", "section", "select", "small", "slot", "source", "span", "strike", "strong", "style", "sub", "summary", "sup", "table", "tbody", "td", "textarea", "tfoot", "th", "thead", "template", "time", "title", "tr", "track", "tt", "u", "ul", "var", "video", "wbr", "xmp"];

let common = xulElements.filter(value => htmlElements.includes(value));

let xulOnly = xulElements.filter(value => !htmlElements.includes(value));