zh:zh|robots.txt robots.txt（统一小写）是一种存放于网站根目录下的ASCII编码的文本文档，它通常告诉网络搜索引擎的漫游器（又称网络蜘蛛），此网站中的哪些内容是不应被搜索引擎的漫游器获取的，哪些是可以被漫游器获取的。因为一些系统中的URL是大小写敏感的，所以robots.txt的文档名应统一为小写。robots.txt应放置于网站的根目录下。如果想单独定义搜索引擎的漫游器访问子目录时的行为，那幺可以将自定的设置合并到根目录下的robots.txt，或者使用robots元数据（Metadata，又称元数据）。

The robots exclusion standard, also known as the robots exclusion protocol or simply robots.txt, is a standard used by websites to communicate with web crawlers and other web robots. The standard specifies how to inform the web robot about which areas of the website should not be processed or scanned. Robots are often used by search engines to categorize web sites. Not all robots cooperate with the standard; email harvesters, spambots and malware robots that scan for security vulnerabilities may even start with the portions of the website where they have been told to stay out. The standard is different from, but can be used in conjunction with Sitemaps, a robot inclusion standard for websites.