弹钢琴的键在JavaScript中的延迟后 [英] Playing piano keys after delay in JavaScript

问题描述

我试图写一个脚本来'玩'在这个在线键盘用JavaScript'点击'我的钥匙。

I was trying to write a script to 'play' some keys on this online keyboard by using JavaScript to 'click' the keys for me.

//sample array to iterate over
var keys_ = ['et', 'dst', 'et', 'dst', 'et', 'b', 'dt', 'ct', 'a', ...];

//handles the clicking only
function playKey(id_) {
    key_ = document.getElementById(id_);
    key_.click(); }

//iterates over the array
function playKeys(keys_) {
    delay = 1000;
    for (i = 0; i < keys_.length; i++) {
        console.log(delay);
        key_ = keys_[i];
        console.log(key_);
        window.setTimeout('playKey(key_)', delay);
        delay += 1000; 
        } 
    }

输出

控制台引发以下错误：

The output

The console throws the following error:

1000结果
  等结果
  2000结果
  DST结果
  ...结果
  9000结果
  一个结果
  未定义的结果
  未捕获类型错误：无法读取空对ano.html财产风格：142结果
  8遗漏的类型错误：不能调用方法'点击'空的

1000
et
2000
dst
...
9000
a
undefined
Uncaught TypeError: Cannot read property 'style' of null p-ano.html:142
8 Uncaught TypeError: Cannot call method 'click' of null

正如你所看到的，延迟和键_ 值是完全正确的。不过还是当我执行这一点，一秒钟后（即1 ^ST 超时），所有的按键似乎玩一次，然后什么也没有发生。

As you can see, the delay and key_ values are perfectly correct. But still when I execute this, after a second (i.e., the 1^st timeout), all the keys seem to play at once and then nothing happens.

我在做什么错了？

的 P.S：我见过像<一个其他问题href=\"http://stackoverflow.com/questions/11492116/how-to-create-a-javascript-that-clicks-a-particular-url-after-a-certain-amount-o\">this 之一和谷歌搜索和其他论坛，都无济于事的

P.S.: I've seen other questions like this one and searched Google and other forums, to no avail

推荐答案

了解有关关闭。

window.setTimeout(function(){ playKey(key_); }, delay);

和你有全局和当地人的一个问题。使用VAR！

and you have a problem with globals and locals. Use var!

我会写这将是该办法

( function() {
    var keys_ = ['et', 'dst', 'et', 'dst', 'et', 'b', 'dt', 'ct', 'a'],
        delay = 250,
        currentIndex = 0,
        playKeys = function () {
            document.getElementById(keys_[currentIndex]).click();        
            currentIndex++;
            if (currentIndex<keys_.length) {
                window.setTimeout(playKeys,delay);
            }    
        };    
    playKeys();
})();

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