I'm learning from various sources and can usually puzzle out what's going on, but this has me a bit stumped. I came across this code at http://www.webdeveloper.com/forum/showthread.php?224180-JQuery-how-does-it-s-insides-work:
function X(css){ //dom utility
//a couple of node harvesters, using id and tag name...
function el(id){ return document.getElementById(id);}
function tags(elm){return document.getElementsByTagName(elm);}
//collect output:
var out=[];
if(css[0]=="#"){//id
out.push(el(css.slice(1)));
}else{//tags
out=out.concat([].slice.call(ta