如何检查用户是否从 <select> 中选择了某些内容HTML5 中的字段？
我看到 <select>不支持新的 required属性...那我必须使用 JavaScript 吗？还是我缺少什么？ :/
最佳答案
强制:将第一个值留空 - 要求对空值起作用
先决条件:正确的 html5 DOCTYPE 和命名输入字段
<select name="somename" required>
<option value="">Please select</option>
<option value="one">One</option>
</select>
根据 the documentation (列表和粗体是我的)
The required attribute is a boolean attribute.
When specified, the user will be required to select a value before submitting the form.If a select element
- has a required attribute specified,
- does not have a multiple attribute specified,
- and has a display size of 1 (do not have SIZE=2 or more - omit it if not needed);
- and if the value of the first option element in the select element's list of options (if any) is the empty string (i.e. present as
value=""),- and that option element's parent node is the select element (and not an optgroup element),
then that option is the select element's placeholder label option.
关于javascript - 我可以将 required 属性应用于 HTML5 中的 <select> 字段吗？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/6048710/