docs: function ElementCollection (elems, context) {
      var elements = nodeListToArray(elems);
      this.context = context;
      this.toArray = function() { return elements; };
  
      this.length = elements.length;
      this.first = elements[0];
      this.last = elements[elements.length-1];
  
      this.get = function(index) {
        if (index === void 0) return elements;
        return elements[index];
      };
    }