bootstra 选择框的样式

image.png

<select class="selectpicker" data-style="btn-primary">
...
</select>

        <select class="selectpicker" data-style="btn-info">
            ...
        </select>

        <select class="selectpicker" data-style="btn-success">
            ...
        </select>

        <select class="selectpicker" data-style="btn-warning">
            ...
        </select>

        <select class="selectpicker" data-style="btn-danger">
            ...
        </select>