(function ($) {
    $.fn.draggable = function (controlelement) {
        var pos1 = 0, pos2 = 0, pos3 = 0, pos4 = 0;
        var elmnt = $(this), ce = controlelement instanceof jQuery ? controlelement : elmnt.find(controlelement);


        function dragMouseDown(e) {
            e.stopPropagation();
            e.preventDefault();
            // get the mouse cursor position at startup:
            pos3 = e.clientX;
            pos4 = e.clientY;
            document.onmouseup = closeDragElement;
            // call a function whenever the cursor moves:
            document.onmousemove = elementDrag;
        }

        function elementDrag(e) {
            e = e || window.event;
            e.preventDefault();
            // calculate the new cursor position:
            pos1 = pos3 - e.clientX;
            pos2 = pos4 - e.clientY;
            pos3 = e.clientX;
            pos4 = e.clientY;
            // set the element's new position:
            elmnt.css('top', (elmnt.offset().top - pos2) + 'px');
            elmnt.css('left', (elmnt.offset().left - pos1) + 'px');
        }

        function closeDragElement() {
            // stop moving when mouse button is released:
            document.onmouseup = null;
            document.onmousemove = null;
        }


        if (typeof controlelement !== 'undefined' && ce.length > 0) {
            ce.mousedown(dragMouseDown).addClass('dctrl');
        } else {
            elmnt.mousedown(dragMouseDown).addClass('dctrl');
        }


        return $(this);
    }
})(jQuery);