只需使用//document-title，它就必须小写，HAP默认将标签小写，我相信原因是xHTML要求标签名称为小写字母，因此HAP可能认为，但不是特定于标准HTML，它可以很好地使用带有大写字母的标记.

Just use //document-title , it jsut need to be lowercase, HAP lowercases the tags by default, i believe the reason is that xHTML required the tag names to be lower-case, so HAP probably considered that, but its not specific to standard HTML, its fine to use tags with capitalization.

更新:经过一些研究后，小写是对xpath的要求，HAP本身对大小写敏感，并且不关心XHTML.

Update: after some research lower case is an xpath requirement, HAP is case insenstive on its own and does not care about XHTML.