// Custom query selector function queryAll(selector) { if (typeof selector !== 'string') return selector; // ID var id_sel = selector.match(/^#([\w-]*)$/); if (id_sel) { var elem = document.getElementById(id_sel[1]); return (elem ? [elem] : []); // Always return an array } // CLASS var class_sel = !id_sel && selector.match(/^\.([\w-]+)$/); if (class_sel) { var elems = document.getElementsByClassName(class_sel[1]); return elems; } // TAG var tag_sel = !class_sel && selector.match(/^[\w-]+$/); if (tag_sel) { var elems = document.getElementsByTagName(selector); return elems; } // Fallback return document.querySelectorAll(selector); } // Prepare DOM elements var elements = ''; for (var i=0, len=10000; i<len; i++){ elements += '<div id="someid" class="someclass el'+i+'">'+i+'</div>'; } document.body.innerHTML += elements;