规范文件：DOM文本节点
我正在阅读文件关于HTML5从我链接的几行下面，显示了示例HTML代码示例DOM树。为什么直接在< head> 元素之前没有文本节点？为什么 DOCTYPE 和< html> 节点之间没有文本节点？错误或功能？
I am reading a document about HTML5. A few lines down from where I linked, a sample DOM tree is displayed for the sample HTML code given. Why is there no text node directly before the <head> element? Why is there no text node between the DOCTYPE and <html> nodes? Error or feature?
功能。主要原因是，鉴于标记
Feature. The main reason is that, given the markup
<!DOCTYPE html>
<html>
<head>
<title>Sample page</title>
...,
有些人希望
document.documentElement.firstChild
返回头元素。但是，如果包含文本节点，那就是要返回的节点。
to return the head element. However, if the text node were included, that is the node that would be returned.
（另请注意，之间的新行; / body> 和< / html> 最终在正文元素中。 ）
(Note, also, that the new line between </body> and </html> ends up in the body element.)