:optional
尝试一下
这个伪类很有用,可以为不是必须提交的表单字段设置样式。
备注: :required
伪类选择必填表单字段
语法
css
:optional {
/* ... */
}
示例
可选字段具有紫色边框
HTML
html
<form>
<div class="field">
<label for="url_input">Enter a URL:</label>
<input type="url" id="url_input" />
</div>
<div class="field">
<label for="email_input">Enter an email address:</label>
<input type="email" id="email_input" required />
</div>
</form>
CSS
css
label {
display: block;
margin: 1px;
padding: 1px;
}
.field {
margin: 1px;
padding: 1px;
}
input:optional {
border-color: rebeccapurple;
border-width: 3px;
}
结果
无障碍考虑
规范
Specification |
---|
HTML Standard # selector-optional |
Selectors Level 4 # opt-pseudos |
浏览器兼容性
BCD tables only load in the browser