get all classess (draft)

$('<script>', {src: '//cdnjs.cloudflare.com/ajax/libs/underscore.js/1.6.0/underscore-min.js'}).appendTo('head');
$(function(){
	var arr = [];
	$('*').each(function(i, el){
		var classe = $(el).attr('class');
		if(classe && classe.length) {
			arr.push(classe.split(' '));
		}
	});
	arr = _(arr).sortBy();
	arr = _(arr).flatten();
	arr = _(arr).uniq();
	console.log(arr);
});