Hint: 你也可以在这个框中插入表达式 (New in 3.0.0 )。请记住表达式的输出不是动态更新的。
According to the W3C, CSS class names can contain only the characters [a-zA-Z, and 0-9] and ISO 10646 characters U+00A1 and higher, plus the hyphen (-) and the underscore (_). They cannot start with a digit, or a hyphen followed by a digit. LimeSurvey encodes CSS classes, but it does not fix it totally.