Bootstrap的modal拖动效果

(function(){  function moveModal($this){    var $head = $this.find('.modal-header');    var $dialog = $this.find('.modal-dialog');    var move = {      isMove: false,      left: 0,      top: 0    };    //委托    console.log('点击的是',$this);    $this.on('mousemove', function(e){      if(!move.isMove) return;      console.log('移动的是', e.target);      $dialog.offset({        top: e.pageY - move.top,        left: e.pageX - move.left      });    }).on('mouseup', function(e){      move.isMove = false;    });    $head.on('mousedown', function(e){      move.isMove = true;      var offset = $dialog.offset();      move.left = e.pageX - offset.left;      move.top = e.pageY - offset.top;    });  }  var oldModal = $.fn.modal;  $.fn.modal = function(o, _r){    var $this = $(this);    if(!$this.attr('ifbindmv')){      $this.attr('isbindmv','1');      moveModal($this);    }    return oldModal.call(this, o, _r);  }  ////要拖动的div背景  //$('#showErr').modal({backdrop: 'static'});})();