mailto automatically generates email links and determines whether to encode address information based on options. Email address encoding makes it difficult for network sniffing programs to collect email address information.

Technical points: Although hex can be used Hexadecimal encoding, but javascript can be considered a very thorough encoding form.

eg:

{mailto address="me@domain.com"}
{mailto address="me@domain.com" text="send me some mail"}
{mailto address="me@domain.com" encode="javascript"}
{mailto address=" me@domain.com" encode="hex"}
{mailto address="me@domain.com" subject="Hello to you!"}
{mailto address="me@domain.com" cc ="you@domain.com,they@domain.com"}
{mailto address="me@domain.com" extra='class="email"'}

Output:
<a href="mailto:me@domain.com" >me@domain.com</a>
<a href="mailto:me@domain.com" > send me some mail</a>
<SCRIPT language="javascript">eval(unescape('document.wr%6
9te('me@domain.com
');'))</SCRIPT>
<a href="mailto:me@domain.com" >&# x6d;e@d&
#x6f;main.co& #x6d;</a>
<a href="mailto:me@domain.com?subject=Hello to you!" >me@domain.com</a>
<a href ="mailto:me@domain.com?cc=you@domain.com,they@domain.com" >me@domain.com</a>
<a href="mailto:me@domain. com" class="email">me@domain.com</a>