HTML Checking for Large Sites

<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 href attribute on an <a> link contains a space character, which is not allowed. If you’re trying to link to a phone URL, review the href attribute to remove unallowed characters, as in this example:

<!-- Invalid as it contains a space character -->
<a href="tel: +123456789">call me</a>

<!-- Valid -->
<a href="tel:+123456789">call me</a>

Source:

• IETF: tel URI for Telephone Numbers

Attributes in HTML elements need to be separated by space, in this example the first line is invalid and the second one is valid:

<a href="page.php"class="big">link</a>

<a href="page.php" class="big">link</a>