我用Bootstrap找到了你的案子。这是最简单的解决方案：

选择表单控件{-moz外观：无；-webkit外观：无；外观：无；背景位置：右中心；背景重复：无重复；背景尺寸：1ex；背景原点：内容框；背景图像：url(“数据：image/svg+xml；base64，PD94bWwgdmVyc2lvbj0iMS4wIiBlbbNvZGluZz0iVVRGLTgiIHN0YW5kYWxvbmU9Im5vIj8+CjxzdmcKICAgeG1sbnM6ZGM9Imh0dHA6Ly9wdXJsLm9y9kYy9lbGVtZW50cy8xLjEvIgogICB4bWxuczpjYz0iaHR0cDovL2NyZWF0aXZlY29tbW9ucy5vcmcvbnMjIgogICB4Wxu czpyZGY9Imh0dHA6Ly93d3cudzMub3JnLzE5OTkvMDIvMjItcmRmLXN5bnRheC1UcyMiCiAgIHhtbG5zOnN2Zz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmicCiAgIHht bG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIKICAgdmVyc2lvbj0iMS4xIgogICBpZD0ic3ZnMiIKICAgdmlld0JveD0iMCAwIDM1Ljk3MDk4MyAyMy4wOTE1MTgiCiAgIGhlaWdodD0iNi41MTY5Mzk2bW0iCiAgIHdpZHRoPSIxMC4NTE4MTFtbSI+CiAgPGRlZnMKICAgICBpZD0ZGVmczQiIC8+CiAgPG1ldGFkYXRhCiAgICAgaWQ9Im1ldGFkYXRhNyI+CiAgICA8cmRmRmJERj4K ICAgICAgPGNjOldvcmsKICAgICAgICAgcmRmOmFib3V0PSIiPgogICAgIDxkYzpmb3JtYXQ+aW1hZ2Uvc3ZnK3htbDwvZGM6Zm9ybWF0GogICAgICgIDxKYzp0eXBlCiAgICAgICAgICAgcmRmOnJlc291cmNlPSJodHRwOi8vcHVybC5vcmcvZGMvZGNtaXR5cGUvU3RpbGxJbWFnZSIgLz4KICAgICAg ICAgICAc8ZGM6dGl0bGU+PC9kYzp0aXRsZT4KICAgPC9jYzpXb3JrGogICAgPC9 yZGY6UkRGPgogIDwvbWV0YWRhdGE+CiAgPGcKICAgICB0cmFuc2Zvcm09InRyYW5zbGF0ZSgtMjAyLj AxNDUxLC00MDcuMTIyMjUpIgogICAgIGlkPSJsYXllcjEiPgogICAgPHRleHQKICAgICAgIGLKPSJ0ZXh0MzMzNiIKICAgICAgIHk9IjYyOS41MDUwNyIKICAgIHg9IjI5MS40Mjg1NiIKICAgICagIHN0eWxlPSJmb250LXeWxlOm5vcm1hbDtmb250LXdlaWdodDpub3JtYWw7Zm9udC1zaXplOjQwcHg7bGluZS1oZlnaHQ6MTI1JTtmb250LWZhbWlseTpzYW5zLXNlcmlmO2xldHRlc1zcGFjaW5nOjBweDt3b3JkLXNwYWpbmc6MHB4O2ZpbGw6IzAwMDAwMDtmaWxsLW9wYWpdHk6MTtzdHJva2U6bm9uZTtzdHJVa2Utd2lkdGg6MXB4O30cm9rZS1saW5lY2FwOmJ1dHQ7c3Ryb2tlLWxpbmVqb2luOm1pdGVyO30cm9 rZS1vcGFjaXR5OjEiCiAgICAgICB4bWw6c3BhY2U9InByZXNlcnZlIj48dHNwYW4KICAgICAgT0iNjI5LjUwNTA3GogICAgICB4PSIyOTEuNDI4NTYiCiAgICAgIGlkPSJ0c3BhbjMzMzgiPjwvdHNwYW4+PC90ZXh0GogICAg PGcKICAgICAgIglkPSJ0ZXh0MzM0MCIKICAgICAgIHN0eWxlPSJmb250LXN0eWXLOm5vcm1hbDtmb250LXZhcmlhbnQ6bm9ybWFsO2ZvbnQtd2VpZ2h0Om5vcm2hbDtmb2 50LXN0cmV0Y2g6bm9yWFsO 2ZvbnQtc2l6ZTo0MHB4O2xpbmUtaGVpZ2h0OjEyNSU7Zm9udC1mYW1pbHk6Rm9udEF3ZXNvbWU7LWlua3NjYXBlLWZvbnqtc3blY2lmaWNhdGlvbjpGb250QXdlc29tZTtsZXR0ZXItc3BhY2luZzowcHg7d29yZC1zcGFjaW5nOjBweDtmaWxsOiMwMDAwMDA7Zmlsbc1vcGFjaXR5OjE7c3 Ryb2tlOm5vbmU7c3 Ryb2tl LXdpZHRojFweDtzdHJva2UtbGluZWNhcDpidXR0O3N0cm9rZS1saW5lam9pbjptaXRlcjtzdHJVa2Utb3BhY2l0eToxIj4KICAgICAgPHBhdGgKICAgICAgICAgaWQ9InBhdGgzMzQ1IggICAgICBzdHls ZT0iZmlsbDojMzMzMz MzO2ZpbGwtb3BhY2l0eToxIggICAgICBkPSJtIDizNy41NjY5Niw0MTMuMjU1MDcgYyAwLjU1ODA0LC0wLjU1OD A0IDAuNTU4MDQsLTEuNDczMjIgMCwtMi4wMzEynSBsIC0zLjcwNTM1LC0zLjY4MzA0IGMgLTauNTU4MDQsLTauNTU4MDQgLTEuNDuwOSwtMC41NTgwNCAtMi4wMDg5MywwIEwgMjIwLDQxOS4zOTM0NiAyMDguMTQ3MzIsNDA3LjU0MDc4IGMgLTAUNTU4MDDMsLTauntU4MDDQgLTeuNDuwodksLTauNTu4MDQgLTEuMDA4OTMsMCBsiC0zLjcw NTM1LDMuNjgzMDQgYyAtMC41NTgwNCwwLjU1ODD AzIC0wLjU1ODA0LDEuNDczMjEgMCwyLjAzMTI1IGwgMTYuNTYyNSwxNi41NDAxNyBjIDAuNTU4MMSC41NTWGNCAxLjQ1MDg5LDAuNTU4MDQgMi4wMDg5MiwwIGwgMTYUNTYyNSSwtMTYuNTQwMTcgeiIgLz4KICAgIDwZz4KICA8L2c+Cjwvc3ZnPgo=“）；}<link href=“https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css“rel=”stylesheet“/><section class=“container”><form class=“form horizontal”><select class=“表单控件”><option>一个</option><option>两个</option></选择></form></section>

注意：base64在SVG中是一个V字形。

对您可以通过标记名来设置任何HTML元素的样式，如下所示：

select {
  font-weight: bold;
}

当然，您也可以像其他任何元素一样使用CSS类来设置其样式：

<select class="important">
  <option>Important Option</option>
  <option>Another Important Option</option>
</select>

<style type="text/css">
  .important {
    font-weight: bold;
  }
</style>

从InternetExplorer10开始，您可以使用：：-ms-expand伪元素选择器来样式和隐藏下拉箭头元素。

select::-ms-expand {
    display:none;
    /* or visibility: hidden; to keep it's space/hitbox */
}

其余的样式应该与其他浏览器类似。

下面是Danield的jsfiddle的一个基本分支，它应用了对IE10的支持

自定义选择CSS样式

在Internet Explorer（10和11）、Edge、Firefox和Chrome中测试

select：：-ms扩展{显示：无；}选择{显示：内联块；框大小调整：边框框；衬垫：0.5em 2em 0.5em 0.5em；边框：1px实心#eee；字体：inherit；线条高度：inherit；-webkit外观：无；-moz外观：无；-ms外观：无；外观：无；背景重复：无重复；背景图像：线性梯度（45deg，透明50%，currentColor 50%），线性梯度（135deg，当前Color 50%，透明50%）；背景位置：右15px顶部1em，右10px顶部1nm；背景尺寸：5px 5px，5px 5px；}<select name=“”><option value=“”>Lorem</option><option value=“”>Lorem Ipsum</option></选择><select name=“”已禁用><option value=“”>禁用</option></选择><select name=“”style=“color:red；”><option value=“”>颜色</选项><option value=“”>Lorem Ipsum</option></选择>

在设置选择下拉列表样式时，我注意到的最大的不一致是Safari和Google Chrome渲染（Firefox可以通过CSS完全自定义）。在互联网的黑暗深处进行了一些搜索后，我发现了以下内容，这几乎完全解决了我对WebKit的疑虑：

Safari和Google Chrome修复程序：

select {
  -webkit-appearance: none;
}

但是，这会删除下拉箭头。您可以使用带有背景、负边距或绝对位于select下拉列表上方的附近div添加下拉箭头。

*CSS属性：-webkit外观中提供了更多信息和其他变量。

我用Bootstrap找到了你的案子。这是最简单的解决方案：

选择表单控件{-moz外观：无；-webkit外观：无；外观：无；背景位置：右中心；背景重复：无重复；背景尺寸：1ex；背景原点：内容框；背景图像：url(“数据：image/svg+xml；base64，PD94bWwgdmVyc2lvbj0iMS4wIiBlbbNvZGluZz0iVVRGLTgiIHN0YW5kYWxvbmU9Im5vIj8+CjxzdmcKICAgeG1sbnM6ZGM9Imh0dHA6Ly9wdXJsLm9y9kYy9lbGVtZW50cy8xLjEvIgogICB4bWxuczpjYz0iaHR0cDovL2NyZWF0aXZlY29tbW9ucy5vcmcvbnMjIgogICB4Wxu czpyZGY9Imh0dHA6Ly93d3cudzMub3JnLzE5OTkvMDIvMjItcmRmLXN5bnRheC1UcyMiCiAgIHhtbG5zOnN2Zz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmicCiAgIHht bG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIKICAgdmVyc2lvbj0iMS4xIgogICBpZD0ic3ZnMiIKICAgdmlld0JveD0iMCAwIDM1Ljk3MDk4MyAyMy4wOTE1MTgiCiAgIGhlaWdodD0iNi41MTY5Mzk2bW0iCiAgIHdpZHRoPSIxMC4NTE4MTFtbSI+CiAgPGRlZnMKICAgICBpZD0ZGVmczQiIC8+CiAgPG1ldGFkYXRhCiAgICAgaWQ9Im1ldGFkYXRhNyI+CiAgICA8cmRmRmJERj4K ICAgICAgPGNjOldvcmsKICAgICAgICAgcmRmOmFib3V0PSIiPgogICAgIDxkYzpmb3JtYXQ+aW1hZ2Uvc3ZnK3htbDwvZGM6Zm9ybWF0GogICAgICgIDxKYzp0eXBlCiAgICAgICAgICAgcmRmOnJlc291cmNlPSJodHRwOi8vcHVybC5vcmcvZGMvZGNtaXR5cGUvU3RpbGxJbWFnZSIgLz4KICAgICAg ICAgICAc8ZGM6dGl0bGU+PC9kYzp0aXRsZT4KICAgPC9jYzpXb3JrGogICAgPC9 yZGY6UkRGPgogIDwvbWV0YWRhdGE+CiAgPGcKICAgICB0cmFuc2Zvcm09InRyYW5zbGF0ZSgtMjAyLj AxNDUxLC00MDcuMTIyMjUpIgogICAgIGlkPSJsYXllcjEiPgogICAgPHRleHQKICAgICAgIGLKPSJ0ZXh0MzMzNiIKICAgICAgIHk9IjYyOS41MDUwNyIKICAgIHg9IjI5MS40Mjg1NiIKICAgICagIHN0eWxlPSJmb250LXeWxlOm5vcm1hbDtmb250LXdlaWdodDpub3JtYWw7Zm9udC1zaXplOjQwcHg7bGluZS1oZlnaHQ6MTI1JTtmb250LWZhbWlseTpzYW5zLXNlcmlmO2xldHRlc1zcGFjaW5nOjBweDt3b3JkLXNwYWpbmc6MHB4O2ZpbGw6IzAwMDAwMDtmaWxsLW9wYWpdHk6MTtzdHJva2U6bm9uZTtzdHJVa2Utd2lkdGg6MXB4O30cm9rZS1saW5lY2FwOmJ1dHQ7c3Ryb2tlLWxpbmVqb2luOm1pdGVyO30cm9 rZS1vcGFjaXR5OjEiCiAgICAgICB4bWw6c3BhY2U9InByZXNlcnZlIj48dHNwYW4KICAgICAgT0iNjI5LjUwNTA3GogICAgICB4PSIyOTEuNDI4NTYiCiAgICAgIGlkPSJ0c3BhbjMzMzgiPjwvdHNwYW4+PC90ZXh0GogICAg PGcKICAgICAgIglkPSJ0ZXh0MzM0MCIKICAgICAgIHN0eWxlPSJmb250LXN0eWXLOm5vcm1hbDtmb250LXZhcmlhbnQ6bm9ybWFsO2ZvbnQtd2VpZ2h0Om5vcm2hbDtmb2 50LXN0cmV0Y2g6bm9yWFsO 2ZvbnQtc2l6ZTo0MHB4O2xpbmUtaGVpZ2h0OjEyNSU7Zm9udC1mYW1pbHk6Rm9udEF3ZXNvbWU7LWlua3NjYXBlLWZvbnqtc3blY2lmaWNhdGlvbjpGb250QXdlc29tZTtsZXR0ZXItc3BhY2luZzowcHg7d29yZC1zcGFjaW5nOjBweDtmaWxsOiMwMDAwMDA7Zmlsbc1vcGFjaXR5OjE7c3 Ryb2tlOm5vbmU7c3 Ryb2tl LXdpZHRojFweDtzdHJva2UtbGluZWNhcDpidXR0O3N0cm9rZS1saW5lam9pbjptaXRlcjtzdHJVa2Utb3BhY2l0eToxIj4KICAgICAgPHBhdGgKICAgICAgICAgaWQ9InBhdGgzMzQ1IggICAgICBzdHls ZT0iZmlsbDojMzMzMz MzO2ZpbGwtb3BhY2l0eToxIggICAgICBkPSJtIDizNy41NjY5Niw0MTMuMjU1MDcgYyAwLjU1ODA0LC0wLjU1OD A0IDAuNTU4MDQsLTEuNDczMjIgMCwtMi4wMzEynSBsIC0zLjcwNTM1LC0zLjY4MzA0IGMgLTauNTU4MDQsLTauNTU4MDQgLTEuNDuwOSwtMC41NTgwNCAtMi4wMDg5MywwIEwgMjIwLDQxOS4zOTM0NiAyMDguMTQ3MzIsNDA3LjU0MDc4IGMgLTAUNTU4MDDMsLTauntU4MDDQgLTeuNDuwodksLTauNTu4MDQgLTEuMDA4OTMsMCBsiC0zLjcw NTM1LDMuNjgzMDQgYyAtMC41NTgwNCwwLjU1ODD AzIC0wLjU1ODA0LDEuNDczMjEgMCwyLjAzMTI1IGwgMTYuNTYyNSwxNi41NDAxNyBjIDAuNTU4MMSC41NTWGNCAxLjQ1MDg5LDAuNTU4MDQgMi4wMDg5MiwwIGwgMTYUNTYyNSSwtMTYuNTQwMTcgeiIgLz4KICAgIDwZz4KICA8L2c+Cjwvc3ZnPgo=“）；}<link href=“https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css“rel=”stylesheet“/><section class=“container”><form class=“form horizontal”><select class=“表单控件”><option>一个</option><option>两个</option></选择></form></section>

注意：base64在SVG中是一个V字形。