ex17

Exercise 5.17 (P143)

Write a variadic function ElementsByTagName that, given an HTML node tree and zero or more names, returns all the elements that match one of those names. Here are two example calls:

    func ElementsByTagName(doc *html.Node, name ...string) []*html.Node
    images := ElementsByTagName(doc, "img")
    headings := ElementsByTagName(doc, "h1", "h2", "h3", "h4")