Question

我有一点问题我无法解决。我做了某种游戏来按键，我使用数字生成器来生成你需要按下的键的数量。当然，你需要能够看到你需要按的字母，而不仅仅是js看到的数字。

<script>
var key = Math.floor(Math.random() * 26 + 97);
var p = -10;
var x;
key = 13;
var letter;

function lespres(event) {                                                           //action when key pressed
clock ();
document.getElementById('key2b').innerHTML = "PRESS KEY: " + key;
x = event.which;
document.getElementById('keypressed').innerHTML = "KEY PRESSED: " + x;

if(x == key)    {                                                                   //correct key action
    p = +p + 10;
    document.getElementById('punten').innerHTML = "POINTS: " + p ;
    key = Math.floor(Math.random() * 26 + 97);
    document.getElementById('key2b').innerHTML = "PRESS KEY: " + key;
}
else            {                                                                   //incorrect key action
    p = +p - 5;
    document.getElementById('punten').innerHTML = "POINTS: " + p ;
}
}
</script>

我创建了一个将密钥号翻译成字母的功能，但我不知道如何在我的代码中实现它。

function lettergen()    {
                        if      (key == 97)     {
                        letter = a;
                        }
                        else if (key == 98)     {
                        letter = b;
                        }
                        else if (key == 99)     {
                        letter = c;
                        }
                    } //and all the way to z

如果我将此函数放入函数lespres并将“key”更改为

中的“letter”

document.getElementById('key2b').innerHTML = "PRESS KEY: " + key;

它说“未定义”。有人能帮帮我吗？帮助我很感激：D

Answer 1

function lettergen() { // !! avoiding side-effects. variable 'letter' can be defined in higher scope var letter = 'unknown'; if (key == 97) { letter = a; } else if (key == 98) { letter = b; } else if (key == 99) { letter = c; } //and all the way to z // !!! return letter; }函数不返回任何内容（返回var KEY_TO_LETTER = { 97: 'a', 98: 'b', } function lettergen(key) { return KEY_TO_LETTER[key] }）

var express = require("express");
var app = express();
var router = express.Router();
var path = __dirname + '/views/';


    router.use(function (req,res,next) {
        console.log("/" + req.method);
        next();
      });

      app.use('/assets', [
        express.static(__dirname + '/assets/'),
      ]);

      router.get("/",function(req,res){
        res.sendFile(path + "");
      });

      app.use("/",router);

      app.use("*",function(req,res){
        res.sendFile(path + "404.html");
      });

P.S。如果你重写你的功能，也许会更简单。尝试使用object而不是if-else语句。

<script src="assets/global/plugins/jquery.min.js" type="text/javascript"></script>
<script src="assets/global/plugins/bootstrap/js/bootstrap.min.js" type="text/javascript"></script>

将键码编号转换为实际字母（js）

1 个答案: