页面滚动后，jQuery可拖动在错误的位置显示助手

This might be a related bug report, it's been around for quite a while: http://bugs.jqueryui.com/ticket/3740

我测试的每个浏览器(Chrome、FF4、IE9)似乎都会发生这种情况.有几种方法可以解决此问题:

1. Use position:absolute; in your css. Absolutely positioned elements don't seem to be affected.

2.确保父元素(如果是主体，则为事件)设置了overflow:auto;.我的测试表明，这个解决方案修复了位置，但它禁用了autoscroll功能.您仍然可以使用鼠标滚轮或箭头键滚动.

3.手动应用上述错误报告中建议的修复程序，并仔细测试是否会导致其他问题.

4. Wait for an official fix. It's scheduled to jQuery UI 1.9, although it has been postponed a few times in the past.

5. If you're confident that it happens on every browser, you can put these hacks into the affected draggables' events to correct the calculations. It's a lot of different browsers to test though, so it should only be used as a last resort:

$('.drag').draggable({
   scroll:true,
   start: function(){
      $(this).data("startingScrollTop",$(this).parent().scrollTop());
   },
   drag: function(event,ui){
      var st = parseInt($(this).data("startingScrollTop"));
      ui.position.top -= $(this).parent().scrollTop() - st;
   }
});