<(?<HtmlTag>[\w]+)[^>]*\s[iI][dD]=(?<Quote>["']?)footer(?(Quote)\k<Quote>)["']?[^>]*>((?<Nested><\k<HtmlTag>[^>]*>)|</\k<HtmlTag>>(?<-Nested>)|[\s\S]*?)*</\k<HtmlTag>>
将footer替换为指定的dom元素id即可。
转自:http://www.cnblogs.com/Daywei/articles/2044466.html