如果元素被标签包装，标签是否需要“for”属性？(If an element is wrapped by a label, does the label require the “for” attribute?)

如果元素被标签包装，标签是否需要“for”属性？(If an element is wrapped by a label, does the label require the “for” attribute?)

假设我有一组收音机<input> 。 我不是一个穴居人，所以我知道我需要将<label>与那些<input> 。 由于这里列举的原因 ，我喜欢将单选按钮包裹在相应的标签中。

所以，例如：

<fieldset> <legend>Should I provide a "for" attribute?</legend> <label><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_yes" value="yes" />Yep, if you know what's good for you</label> <label><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_no" value="no" />ah, that would be redundant and repetitive</label> </fieldset>

这个包装将相应的单选按钮与标签相关联。 我是否也需要定义标签的属性？

<fieldset> <legend>Should I provide a "for" attribute?</legend> <label for="define_the_for_attribute_yes"><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_yes" value="yes" />Yep, if you know what's good for you</label> <label for="define_the_for_attribute_no"><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_no" value="no" />ah, that would be redundant and repetitive</label> </fieldset>

正如 @Peter 指出的那样 ，“标签元素的for属性必须引用一个表单控件”（见http://www./TR/html-markup/label.html ），但这可以被读取意思是“如果你指定了可选for属性，它必须引用一个有效的表单控件”。

Say I have a set of radio <input>s. I'm not a caveman, so I know I need to associate <label> with those <input>s. I'm fond of wrapping the radio butt within their corresponding labels, for reas enumerated here.

So, for example:

<fieldset> <legend>Should I provide a "for" attribute?</legend> <label><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_yes" value="yes" />Yep, if you know what's good for you</label> <label><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_no" value="no" />ah, that would be redundant and repetitive</label> </fieldset>

This wrapping associates the corresponding radio button with the label. Do I also need to define the label's for attribute?

<fieldset> <legend>Should I provide a "for" attribute?</legend> <label for="define_the_for_attribute_yes"><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_yes" value="yes" />Yep, if you know what's good for you</label> <label for="define_the_for_attribute_no"><input type="radio" name="define_the_for_attribute" id="define_the_for_attribute_no" value="no" />ah, that would be redundant and repetitive</label> </fieldset>

As pointed out by @Peter, "The for attribute of the label element must refer to a form control" (see http://www./TR/html-markup/label.html), but this could be read to mean "if you specify the optional for attribute, it must refer to a valid form control".

最满意答案

根据HTML5规范 - “如果没有指定for属性，但标签元素具有可描述的元素后代，那么第一个树形顺序的后代是标签元素的标签控件。”

http://www./TR/html5/forms.html#category-label

所以基本上不需要，只要它包装任何这些元素：按钮，输入（如果type属性不处于隐藏状态），keygen，仪表，输出，进度，选择或textarea

According to the HTML5 spec - "If the for attribute is not specified, but the label element has a labelable element descendant, then the first such descendant in tree order is the label element's labeled control."

http://www./TR/html5/forms.html#category-label

So basically, no it is not required as long as it is wrapping any of these elements: button, input (if the type attribute is not in the hidden state), keygen, meter, output, progress, select, or textarea