[javascript] Automatically open default email client and pre-populate content

As described by RFC 6068, mailto allows you to specify subject and body, as well as cc fields. For example:

mailto:[email protected]?subject=Subject&body=message%20goes%20here

User doesn't need to click a link if you force it to be opened with JavaScript

window.location.href = "mailto:[email protected]?subject=Subject&body=message%20goes%20here";

Be aware that there is no single, standard way in which browsers/email clients handle mailto links (e.g. subject and body fields may be discarded without a warning). Also there is a risk that popup and ad blockers, anti-virus software etc. may silently block forced opening of mailto links.