HTML复选框的checked属性的值是什么？ [英] What's the proper value for a checked attribute of an HTML checkbox?

问题描述

我们都知道如何在HTML中形成复选框输入：

We all know how to form a checkbox input in HTML:

<input name="checkbox_name" id="checkbox_id" type="checkbox">

我不知道什么是复选框的技术上正确的值？我已经看到这些工作：

What I don't know -- what's the technically correct value for a checked checkbox? I've seen these all work:

<input name="checkbox_name" id="checkbox_id" type="checkbox" checked>
<input name="checkbox_name" id="checkbox_id" type="checkbox" checked="on">
<input name="checkbox_name" id="checkbox_id" type="checkbox" checked="yes">
<input name="checkbox_name" id="checkbox_id" type="checkbox" checked="checked">
<input name="checkbox_name" id="checkbox_id" type="checkbox" checked="true">

答案是否没关系？我没有看到标记为正确的答案的证据此处来自规范本身：

Is the answer that it doesn't matter? I see no evidence for the answer marked as correct here from the spec itself:

复选框（和单选按钮）是开/关开关，用户可以切换
。当控制元素的选中
属性被设置时，开关是on。当表单提交时，只有on复选框
控件可以成功。表单中的几个复选框可以共享
相同的控件名称。因此，例如，复选框允许用户
为同一属性选择几个值。 INPUT元素用于
创建复选框控件。

Checkboxes (and radio buttons) are on/off switches that may be toggled by the user. A switch is "on" when the control element's checked attribute is set. When a form is submitted, only "on" checkbox controls can become successful. Several checkboxes in a form may share the same control name. Thus, for example, checkboxes allow users to select several values for the same property. The INPUT element is used to create a checkbox control.

规范作者说的是正确的答案？请提供循证解答。

What would a spec writer say is the correct answer? Please provide evidence-based answers.

推荐答案

严格来说，您应该根据规范=http://www.w3.org/TR/html-markup/input.checkbox.html>此处，最正确的版本是：

Strictly speaking, you should put something that makes sense - according to the spec here, the most correct version is:

<input name="name" id="id" type="checkbox" checked="checked">

对于HTML，您还可以使用空属性语法， checked = c $ c>已选中（对于更严格的XHTML，这是不支持的）。

For HTML, you can also use the empty attribute syntax, checked="", or even simply checked (for stricter XHTML, this is not supported).

然而，有效地，大多数浏览器将只支持引号之间的任何值。将检查所有以下内容：

Effectively, however, most browsers will support just about any value between the quotes. All of the following will be checked:

<input name="name" id="id" type="checkbox" checked>
<input name="name" id="id" type="checkbox" checked="">
<input name="name" id="id" type="checkbox" checked="yes">
<input name="name" id="id" type="checkbox" checked="blue">
<input name="name" id="id" type="checkbox" checked="false">

只有以下选项才会取消选中：

And only the following will be unchecked:

<input name="name" id="id" type="checkbox">

另请参见 disabled =disabled 。

这篇关于HTML复选框的checked属性的值是什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！