Отключить JavaScript отключить мыши
document.oncontextmenu = document.body.oncontextmenu = function() {return false;}
Mobile Star
document.oncontextmenu = document.body.oncontextmenu = function() {return false;}
document.addEventListener('contextmenu', event => event.preventDefault());
// ⇓ Test it (fiddle) ⇓
document.addEventListener('contextmenu', event => event.preventDefault());