How to filter elements returned by QuerySelectorAll

I don’t think I get the question right. Why would you want to “filter” the result of querySelectorAll() which infact, is some kind of a filter itself. If you query for div span or even better #id div, those results are already filtered, no ?

However, you can apply Array.prototype.filter to the static result of querySelectorAll like follows:

var filter   = Array.prototype.filter,
    result   = document.querySelectorAll('div'),
    filtered = filter.call( result, function( node ) {
        return !!node.querySelectorAll('span').length;
    });

That code would first use querySelectorAll() to query for all <div> nodes within the document. Afterwards it’ll filter for <div> nodes which contain at least one <span>. That code doesn’t make much sense and is just for demonstrative purposes (just in case some SO member wants to create a donk comment)

update

You can also filter with Element.compareDocumentPosition. I’ll also tell if Elements are disconnected, following, preceding, or contained. See MDC .compareDocumentPosition()