HTML Guide
An input element cannot be placed inside a button element because the HTML standard prohibits interactive content as descendants of a button.
According to the HTML specification, interactive content (like input, button, select, etc.) must not be nested inside button elements. This restriction exists to prevent invalid or unpredictable behavior in user interfaces. For accessible and valid markup, each form control should be a separate, direct child of its container, not nested inside another interactive element.
Example of invalid HTML
<button>
Submit
<input type="text" name="example">
</button>Correct HTML structure
<form>
<input type="text" name="example">
<button type="submit">Submit</button>
</form>
Always ensure that form elements such as input and button are not nested within each other. Keep them as siblings within a form or appropriate container.
Learn more:
Related W3C validator issues
The button role is used to make an element appear as a button control to a screen reader and can be applied to otherwise non-interactive elements like <div>. If you’re already using an <input> element whose type is submit, then it’s redundant to apply it the role button, as that’s implicit.
<!-- Instead of this -->
<input type="submit" role="button">Buy</button>
<!-- Do this -->
<input type="submit">Buy</button>An element with role=button can’t have an input element as descendant.
The ARIA role button can be added to an element to make it behave like a <button> – just like a <button> is not allowed to contain other <input> elements as descendants, any element with this role is not allowed to contain them either.
All these examples in the following code will raise a similar issue:
<div role="button">
<input type="checkbox" />
</div>
<button>
<input type="checkbox" />
</button>
<a>
<input type="checkbox" />
</a>A button element, or an element with the role=button attribute, is not allowed to be nested inside an <a> element.
A button element cannot contain a descendant element with the attribute tabindex.
The autocomplete attribute is used to control if the browser can provide assistance in filling out form field values, and it only makes sense for visible, not hidden, inputs.
It is available on <input> elements that take a text or numeric value as input, <textarea> elements, <select> elements, and <form> elements.
To fix this issue, you can remove the autocomplete attribute from the input element with type=hidden. Here is an example:
<!-- Wrong code -->
<input type="hidden" name="phone" value="12345" autcomplete="off">
<!-- Correct code -->
<input type="hidden" name="phone" value="12345">The aria-* attributes are part of the WAI-ARIA (Web Accessibility Initiative-Accessible Rich Internet Applications) suite. They are used to improve the accessibility of web pages. However, when we use an input element with a type attribute whose value is hidden, we imply that the element is invisible and has no interaction with the user. Therefore, it doesn’t make sense to add aria-* attributes to it.
To fix this issue, you need to remove the aria-* attributes from the input element with type=hidden. Here is an example:
<!-- Wrong code -->
<input type="hidden" name="referer" value="https://example.com" aria-invalid="false">
<!-- Correct code -->
<input type="hidden" name="referer" value="https://example.com">When nesting an input element inside a label that has a for attribute, the id attribute of the input is required to match it.
The label element represents a caption in a user interface. The caption can be associated with a specific form control, known as the label element’s labeled control, either using the for attribute, or by putting the form control inside the label element itself.
When the input is inside the label, there’s no need to specify a for attribute as there can only be one input, as in this example:
<label>
Age
<input type="text" name="age">
</label>However, if the for attribute is specified, then it must match the id of the input like this:
<label for="user_age">
Age
<input type="text" name="age" id="user_age">
</label>The maxlength attribute can be used on an input element to define a client-side validation for the maximum length allowed on an input without resorting to JavaScript.
This attribute is only allowed on elements of type email, password, search, tel, text, or url.
The minlength attribute can be used on an input element to define a client-side validation for the maximum length allowed on an input without resorting to JavaScript.
This attribute is only allowed on elements of type email, password, search, tel, text, or url.
The minlength attribute defines the minimum number of characters (as UTF-16 code units) the user can enter into an <input> or <textarea>. This must be an integer value 0 or higher. If no minlength is specified, or an invalid value is specified, the input has no minimum length. This value must be less than or equal to the value of maxlength, otherwise the value will never be valid, as it is impossible to meet both criteria.
Here’s an example:
<label for="name">Enter your name (max 25 characters)</label>
<input type="text" minlength="25" id="name">The pattern attribute is only allowed on input whose type is email, password, search, tel, text or url. Check the type used, and consider changing to one of the allowed types to enable pattern client-side validation.
The pattern attribute is a handy way of adding client-side validation on HTML forms without resorting to JavaScript. Check out this article to learn more about Input Pattern.