javascript - 为什么DOM树是oder preorder，深度优先遍历？

Question

为什么DOM树是先序，深度优先遍历？

与 BFT 等其他遍历相比，这种设计选择有什么优势？

我只是在调查 DOM standard并找到了 preceding 和 following 的定义:

An object A is preceding an object B if A and B are in the same tree and A comes before B in tree order.

An object A is following an object B if A and B are in the same tree and A comes after B in tree order.

Just like most programming paradigms the Web platform has finite hierarchical tree structures, simply named trees. The tree order is preorder, depth-first traversal.

Answer 1

深度优先遍历通常是最简单的遍历样式，因为您可以递归地或使用显式堆栈进行；广度优先需要一个队列，从某种意义上说，它是一个更复杂的数据结构。但我认为有一个比传统或简单性更简单的答案:(X)HTML 树的深度搜索遍历导致文本节点按呈现顺序遍历。

考虑一下这个相对简单的 HTML子树。

或者，以原始形式:

<p>Consider this <emph>relatively</emph> simple <a href="...">HTML</a> subtree</p>

作为一棵树(省略空格和属性):

                      <P>
                       |
      +-----------+----+----+-----+------+               
______|______   __|___   ___|__  _|_  ___|___
Consider this   <EMPH>   simple  <A>  subtree
                  |               |
              ____|_____        __|__
              relatively         HTML

深度优先遍历:

<P>, Consider this, <EMPH>, relatively, simple, <A>, HTML, subtree

广度优先遍历:

<P>, Consider this, <EMPH>, simple, <A>, subtree, relatively, HTML