HTML Guide for mailto

Bad value “mailto: X” for attribute “href” on element “a”: Illegal character in scheme data: space is not allowed.

bad value
mailto
href
a
space

<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>