$("body").delegate(

            ".msg-layer",{

                mousedown: function (e) {

                    var el = $(".msg-layer");

                    var os = el.offset(),

                    dx = e.pageX - os.left, dy = e.pageY - os.top;

                    $(document).on('mousemove.drag', function (e) {

                        el.offset({top: e.pageY - dy, left: e.pageX - dx});

                    });

                },

                mouseup: function (e) {

                    $(document).off('mousemove.drag');

                }

            }

    );