本例程演示了如何使用正则表达式解析HTML文件。本例程使用C#语言编写，可以下载指定网页并进行分析，将HTML文档结构以树状形式展现出来，并提供基于正则表达式的搜索功能，用户可以方便的筛选出网页上形式相似的内容。-the routine demonstration of how to use regular expressions are analytic HTML document. Routine use of the C# language, designated website can be downloaded and analyzed, HTML files in a tree structure of the form shown, and to provide regular expression is based on the search function, users can select a convenient form on the website similar to the content.