HTML Checking for Large Sites

The autocomplete attribute is not valid on input types that do not return numeric or text data, being valid for all input types except checkbox, radio, file, or any of the button types.

The value company is not a valid option for the autocomplete attribute on an <input> element. You may use the organization value instead, as it can be used for “company name corresponding to the person, address, or contact information in the other fields associated with this field”.

All HTML elements may have the hidden boolean attribute set. When specified on an element, it indicates that the element is not yet, or is no longer, relevant, so browsers won’t render it.

Boolean attributes don’t accept values, its presence represents the true value and its absence represents the false value.

<!-- This is invalid because the hidden attribute should not have a value set -->
<div hidden="false"></div>

<!-- The correct way to hide a div is like this -->
<div hidden>This will be hidden</div>

<!-- And to show the element, we just don't hide it -->
<div>This won't be hidden</div>

An <a> element has been found with an invalid href attribute, containing more than one # adjacent character.

The # is used to separate the fragment part of an URI (typically used to indicate a section within a document). For example, this is a valid link to a URI containing a fragment:

<a href="https://example.com/faqs#pricing">pricing</a>

The next example is invalid because it contains two adjacent # characters, so that the fragment part would be #pricing instead of pricing:

<a href="https://example.com/faqs##pricing">pricing</a>

The href attribute of an <a> element contains an invalid character, that should be properly encoded as a URI percent-encoded character.

The src attribute on an <img> element contains an invalid character, that should be properly encoded as a URI percent-encoded character.

<a> tags can be used to link to an email address using the mailto protocol in the href attribute. Ensure that there is no space in the email address.

<a href="mailto: liza@example.com">This is wrong as it contains an space</a>

<a href="mailto:liza@example.com">This is OK</a>

The correct way to disable autocomplete is using the value off.

Example:

<form autocomplete="off">

The correct way to disable autocomplete is using the value off.

Example:

<input type="text" name="firstName" id="firstName" required autocomplete="off" />

The correct way to disable autocomplete is using the value off.

Example:

<input type="text" name="firstName" id="firstName" required autocomplete="off" />