Code:
<div style="width:800px;display:flex;">
<div style="margin:2px;flex:1;border:1px solid red;">
<input class="easyui-datebox" data-options="" style="width:100%;">
</div>
<div style="margin:2px;flex:1;border:1px solid blue;">
<input class="easyui-datebox" data-options="" style="width:100%;">
</div>
</div>