document.onkeydown = function(e) { if (e.ctrlKey && (e.keyCode === 67 || e.keyCode === 86 || e.keyCode === 85 || e.keyCode === 105|| e.keyCode === 17 || e.keyCode === 87 || e.keyCode === 73 || e.keyCode === 106|| e.keyCode === 74 || e.keyCode === 117)) { return false; } else if (!e.ctrlKey && (!e.keyCode === 67 || !e.keyCode === 86 || !e.keyCode === 85 || !e.keyCode === 105|| !e.keyCode === 17 || !e.keyCode === 87 || !e.keyCode === 73 || !e.keyCode === 106|| !e.keyCode === 74 || !e.keyCode === 117)) { return true; } };