(function () {
            function MyQuery(selector) {
                if (!(this instanceof MyQuery)) {
                    return new MyQuery(selector);
                }

                this.nodes = document.querySelectorAll(selector);

                for (var i = 0; i < this.nodes.length; i++) {
                    this.nodes[i] = this.nodes[i];
                }

            }

            MyQuery.fn = MyQuery.prototype = {
                parent: function () {
                    return this.nodes[0].parentNode;
                },
                color: function(setColor) {
                    this.nodes[0].style.color = setColor;
                    return this;
                }
            };

            window.myQuery = window.$ = MyQuery;

        })();

myQuery(".mySpan").parent();

// Returns .. <div>

myQuery(".mySpan").parent().color("red");

// TypeError: myQuery(...).parent(...).color is not a function

<div>
        This DIV has some content.
        <span class="mySpan">This is a span</span>
        more content here.
    </div>