 window.onload = function() {
    document.addEventListener("contextmenu", function(e){
      e.preventDefault();
    }, false);
    document.addEventListener("keydown", function(e) {
    //document.onkeydown = function(e) {
      // "I" key
      if (e.ctrlKey && e.shiftKey && e.keyCode == 73) {
        disabledEvent(e);
      }
      // "J" key
      if (e.ctrlKey && e.shiftKey && e.keyCode == 74) {
        disabledEvent(e);
      }
      // "S" key + macOS
      if (e.keyCode == 83 && (navigator.platform.match("Mac") ? e.metaKey : e.ctrlKey)) {
        disabledEvent(e);
      }
      // "U" key
      if (e.ctrlKey && e.keyCode == 85) {
        disabledEvent(e);
      }
      // "F12" key
      if (event.keyCode == 123) {
        disabledEvent(e);
      }
    }, false);
    function disabledEvent(e){
      if (e.stopPropagation){
        e.stopPropagation();
      } else if (window.event){
        window.event.cancelBubble = true;
      }
      e.preventDefault();
      return false;
    }
  };