javascript-HTML5中约束验证的只读元素候选

HTML5 specification指出：

A submittable element is a candidate for constraint validation except when a condition has barred the element from constraint validation. (For example, an element is barred from constraint validation if it is an object element.)

验证步骤包括：

For each element field in controls, in tree order, run the following substeps:

1. If field is not a candidate for constraint validation, then move on to the next element.
2. Otherwise, if field satisfies its constraints, then move on to the next element.
3. Otherwise, add field to invalid controls.

我想知道为什么此代码无法按预期工作：

'use strict';

alert(document.getElementById('foo').willValidate); // expected: true; true
alert(document.getElementById('bar').willValidate); // expected: true; false
alert(document.getElementById('baz').willValidate); // expected: false; false

alert(document.getElementById('foo').checkValidity()); // expected: false; false
alert(document.getElementById('bar').checkValidity()); // expected: false; true

<input type=text required id=foo>
<input type=text required id=bar readonly>
<input type=text required id=baz disabled>

这是用户代理实施中的错误还是预期的？

解决方法:

在这里看看：http://www.w3c-test.org/html/semantics/forms/constraints/form-validation-willValidate.html

输入类型=“文本”的条件之一是：

Must be barred from the constraint validation if it is readonly

仅供参考：假设只读元素已经包含一个值,并且通常不需要必需的属性.

标签：html5,validation,html-form,javascript
来源： https://codeday.me/bug/20191028/1951365.html