Bootstrap模态框水平垂直居中与增加拖拽功能

$("#myModal").draggable({ 
handle: ".modal-header", 
cursor: 'move', 
refreshPositions: false 
}); 

/* center modal */ 
function centerModals() { 
$('#myModal').each(function(i) { 
var $clone = $(this).clone().css('display', 'block').appendTo('body'); var top = Math.round(($clone.height() - $clone.find('.modal-content').height()) / 2); 
top = top > 0 "margin-top", top); 
}); 
} 
$('#myModal').on('show.bs.modal', centerModals); 
$(window).on('resize', centerModals); 

<!-- Modal --> 
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true"> 
<div class="modal-dialog"> 
<div class="modal-content"> 
<div class="modal-header"> 
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button> 
<h4 class="modal-title" id="myModalLabel">标题</h4> 
</div> 
<div style="padding:5px;"> 
<div class="modal-body" data-scrollbar="true" data-height="200" data-scrollcolor="#000"> 

</div> 
</div> 
<div class="modal-footer"> 
<button type="button" class="btn btn-default" data-dismiss="modal">关闭</button> 
</div> 
</div> 
</div> 
</div>