HTML5 now allows native context menu manipulation:
https://www.w3.org/blog/2016/11/html-5-1-is-the-gold-standard/?pk_campaign=feed&pk_kwd=html-5-1-is-the-gold-standard
Some time until adopted http://caniuse.com/#feat=menu
EDIT: Chrome removed support, because there's a lack of interest and people don't like the spec (should be JS based, not HTML based).
https://www.w3.org/blog/2016/11/html-5-1-is-the-gold-standard/?pk_campaign=feed&pk_kwd=html-5-1-is-the-gold-standard
Some time until adopted http://caniuse.com/#feat=menu
EDIT: Chrome removed support, because there's a lack of interest and people don't like the spec (should be JS based, not HTML based).