[Bug Report] Android低版本内容很长页面底部弹出popup没有选项

### Mint UI version
2.2.9

### OS/Browsers version
Galaxy S4 Android4.2.2自带浏览器

### Vue version
2.4.2

### Reproduction Link
[https://github.com/ElemeFE/mint-ui/](https://github.com/ElemeFE/mint-ui/)

### Steps to reproduce
1.编写一个内容长度比较长的页面，大约3屏，在内容底部添加一个按钮，点击按钮会触发弹出popup
2.使用Android4.2.2系统浏览器打开该页面
3.滑到页面底部，点击按钮，查看popup效果

### What is Expected?
1.ios、android手机浏览器都正常弹出popup

### What is actually happening?
1.ios正常
2.android4.2.2系统只出现黑色半透明背景，没有弹出pop可选项
3.如果把触发动作放在页面的头部，可以正常弹出可选项。
4.如果把触发动作放在页面中间或页面底部pop可选项弹不出。

Start by opening the mint-ui repository and reproducing the popup behavior on the reported Galaxy S4 Android 4.2.2 browser, using a long page with the trigger at the bottom. Compare the result with triggers near the top and middle. Done means the popup options appear correctly when opened from the bottom on the affected browser.

Written by the indexing model from the issue text.