what is the correct way to code a link that when clicked will send an email to with a subject code example

Example: html email link

<!-- Those percent twenty things be HTML Encoded spaces old bean, true magic. Not that Dynamo nonsense -->
<a href="mailto:[email protected]?Subject=Summat%20or%20Other&body=I%20Have%20been%20for%20a%20massive%20poo">Sendeth This Mail</a>