dataattributes instead of nested and hidden
<span>s to store the additional data.
.jsfile so it can be cached.
titlevalue to "This date and/or time has been adjusted to match your timezone" so the user knows it's been adjusted.
is_feed()check later so it'll actually work.
U(i.e. a Unix timestamp), then don't modify the output as it's most likely being used by PHP rather than being displayed.