Do we still have to set checkboxes to indeterminate using Javascript?

This question was asked back in 2009 and the most recent answers are from 2011, which suggest that you need to use Javascript to set a checkbox to an indeterminate state.

Is this still the case, or is there HTML5 markup now supported by browsers for this scenario?

I ask because this has to be a common requirement, and it seems odd to have it only accessible via Javascript.