javascript - 任何人都可以解释以下 javascript RE 代码吗？

Question

谁能解释一下下面的示例代码？它来自最后一个例子 here .

不知道为什么在 '.' 之前没有 '\' ，可以通过添加 '\'.

JavaScript:

var url = "http://xxx.domain.com";
print(/[^.]+/.exec(url)[0].substr(7)); // prints "xxx"

Answer 1

注意段落here关于字符类中的元字符

Note that the only special characters or metacharacters inside a character class are the closing bracket (]), the backslash (\), the caret (^) and the hyphen (-). The usual metacharacters are normal characters inside a character class, and do not need to be escaped by a backslash.