[Javascript] 키보드 입력 키값
    - 자바스크립트 keyboard event key value 
KeyboardEvent 
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent 
예제
document.addEventListener("keydown", (event) => {
            const keyName = event.key;
            if (keyName === "Control") {
                console.log(`Ctrl 키 눌림`);
                return;
            }
            if (event.ctrlKey) {
                // Ctrl 키와 다른 키의 조합
                console.log(`Ctrl 키 + ${keyName}`);
            } else {
                console.log(`키 = ${keyName}`);
            }
        },
        false
    );
    document.addEventListener("keyup", (event) => {
            const keyName = event.key;
            if (keyName === "Control") {
                console.log("Ctrl 키 해제");
            }
        },
        false
    );
//------------------------------------- 
* 보조키 눌렸는지 여부 판정 
altKey - 좌 
ctrlKey - 좌 
shiftKey - 좌, 우  
//------------------------------------- 
* KeyboardEvent.code 
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/code 
    - 코드값 
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/code/code_values 
        - 멀티미디어 키값 없음 
//------------------------------------- 
* KeyboardEvent.key 
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/key 
    - 키값 
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/key/Key_Values 
    - 멀티미디어 키값 있음 
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/key/Key_Values#multimedia_keys 
MediaStop  , MediaPlayPause  , MediaTrackPrevious  , MediaTrackNext  
AudioVolumeMute , AudioVolumeDown , AudioVolumeUp  
//
| KeyboardEvent | ||
| code | key | |
| ControlLeft | Control | |
| ControlRight | HanjaMode | |
| AltLeft | Alt | |
| AltRight | HangulMode | |
| ShiftLeft | Shift | |
| ShiftRight | Shift | |
| Enter | Enter | |
| NumpadEnter | Enter | |
| Digit1 | 1 | |
| KeyA | a | |
| Tab | Tab | |
| F1 | F1 | |
| Escape | Escape | |
| Backslash | \ | |
| Slash | / | |
| Numpad0 | Insert or 0 | |
| 멀티미디어 키 | 없음 | MediaStop , MediaPlayPause , MediaTrackPrevious , MediaTrackNext | 
| 없음 | AudioVolumeMute , AudioVolumeDown , AudioVolumeUp | |
//
//------------------------------------- 
* 삭제 예정 (Deprecated) 
keypress 이벤트 
KeyboardEvent.keyCode 
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode 
KeyboardEvent.charCode - 모두 0 
//----------------------------------------------------------------------------- 
< 참고 > 
JavaScript Keycode List – Keypress Event Key Codes for Enter, Space, Backspace, and More 
https://www.freecodecamp.org/news/javascript-keycode-list-keypress-event-key-codes/