SO - 29861778

by Arun P Johny

HTML

<div id="parent">
    <div class="stay">Stay</div>
    <div class="stay">Stay</div>
    <div class="go">Go</div>
    <div class="element">element</div>
</div>

JavaScript

var els = document.querySelectorAll('#parent :not(.stay)');
for (var i = 0; i < els.length; i++) {
    els[i].parentNode.removeChild(els[i])
}