<el-row>
<el-col :span="8">
<div>1</div>
</el-col>
<el-col :span="8">
<div><button class="btn draw-border">提交</button></div>
</el-col>
<el-col :span="8">
<div>2</div>
</el-col>
</el-row>
使得三个div在一行内垂直居中显示：
在el-row中增加：type=“flex” align=“middle”
<el-row type="flex" align="middle">
...
</el-row>
