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 () {
 $('body').off("mousemove");
 });
}