How about ```Traversing.nextWhile(node, function (node) { return node.nextSibling && !Html.isRendered(node); });```,
or even better ```Traversing.nextWhile(node, Fn.and(Traversing.nextSibling, Fn.complement(Html.isRendered)))``` (where ```Fn.and``` has to be implemented like in http://docs.closure-library.googlecode.com/git/closure_goog_functions_functions.js.html and ```Traversing.nextSibling``` has to be exported).