bootstrap如何拖拽组件

Modal.DEFAULTS = {
 backdrop: true,
 keyboard: true,
 show: true
}
//新加入的拖拽
Modal.prototype.draggable = function () {
 var $ele = this.$element;
 var mouseOffset;
 var $modalDialog = $ele.find(".modal-dialog");
 var dialogOffset;
 
 $ele.find(".modal-header").on('mousedown', function (event) {
 $(this).addClass({cursor: 'move'});
 $('body').addClass('select');
 dialogOffset = $modalDialog.offset();
 mouseOffset = {
  top: event.pageY - dialogOffset.top,
  left: event.pageX - dialogOffset.left
 };
 $('body').on("mousemove", function (event) {
  var left = event.pageX - mouseOffset.left;
  var top = event.pageY - mouseOffset.top;
  if (left < 10) {
  left = 0;
  } else if (left > $(window).width() - $modalDialog.width()) {
  left = $(window).width() - $modalDialog.width();
  }
  if (top < 10) {
  top = 0;
  } else if (top > $(window).height() - $modalDialog.height()) {
  top = $(window).height() - $modalDialog.height();
  }
  $modalDialog.offset({
  top: top,
  left: left
  });
 });
 });
 
 $(document).on("mouseup mouseleave", function () {
 $(&#39;body&#39;).off("mousemove");
 });
}

Modal.prototype.show = function (_relatedTarget) {
    var that = this
    var e = $.Event('show.bs.modal', {relatedTarget: _relatedTarget})
 
    this.$element.trigger(e)
 
    if (this.isShown || e.isDefaultPrevented()) return
 
    this.isShown = true
 
    //调用draggable()增加拖拽
    this.draggable()
    this.checkScrollbar()
    this.setScrollbar()
    this.$body.addClass('modal-open')
 
    this.escape()
    this.resize()
    //......省略
}