<script>

 function click(e) {
 if (document.all) {
 if (event.button == 2 || event.button == 3) {
          oncontextmenu = 'return false';
        };
      };
 if (document.layers) {
 if (e.which == 3) {
          oncontextmenu = 'return false';
        };
      };
    };
 if (document.layers) {
      document.captureEvents(Event.MOUSEDOWN);
    };
    document.onmousedown = click;
    document.oncontextmenu = new Function("return false;")

    document.onkeydown = document.onkeyup = document.onkeypress = function () {
 if (window.event.keyCode == 123) {
        window.event.returnValue = false;
 return (false);
      };
    };
    
</script>

参考
网页如何禁止鼠标右键和F12,键盘另存为、粘贴、复制事件
HTML屏蔽F12、右键、开发者工具、审查元素