JavaScript的：对不起，我们总是能够索引到的字符串，就像是一个数组？ [英] JavaScript: Have we always been able to index into a string like it's an array?
问题描述
我一直认为，如果你要访问一个名为 STR 字符串，那么你必须做一些像 str中第n个字符.charAt（N）。今天，我正在一点点假人的测试页和误，我与海峡[N] 让我吃惊访问它，它返回我的字符串的第n个字符。我扔了这小目的建造页面出现此意外的（对我）的行为：
I've always thought that if you want to access the nth character in a string called str, then you have to do something like str.charAt(n). Today I was making a little dummy test page and by mistake, I accessed it with str[n] and to my surprise, it returned me the nth character of the string. I threw up this little purpose built page to exhibit this unexpected (to me) behaviour:
<!doctype html>
<html>
<body>
<script>
var str = "ABCDEFGH";
if (str[4] === str.charAt(4)) alert("strings can be indexed directly as if they're arrays");
var str2 = new String("ABCDEFGH");
if (str2[4] === str2.charAt(4)) alert("even if they're declared as object type String");
</script>
</body>
</html>
这是不是总是这样，对吧？
It wasn't always like this, was it?
推荐答案
没有，那是不可能的。
如果你在一个足够老浏览器中运行code，IE 7例如，将无法访问字符串这样。在这些较旧的发动机，你必须使用 .charAt（指数）代替。
If you run your code in an old enough browser, IE 7 for example, it won't be able to access the string like that. On those older engines, you'd have to use .charAt(index) instead.
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