you’re on your way �
231
the document object model
Remember that big huge
DOM tree we just looked at?
Here’s the DOM tree for
the HTML you looked at
back on page 220.
You can get to this whole thing using the
“document” variable in your JavaScript.
You can grab the <html> root element from an HTML
document using the documentElement property:
var htmlElement = document.documentElement;
Get the root element of the document
You’ve already seen several ways to use the
document object in your code... here are a few
reminders from earlier in this chapter.
You’ve already seen how getElementById() makes it
a piece of cake to nd an element in your web page, using
the element’s id attribute.
var manganese =
document.getElementById(“Mg”).value;
Find an element by its “id” attribute
This gets the element
with an id of “Mg”.
head
title
“Binary Tree
Selection”
p
“Below are two
binary tree
options:”
“depth-rst”
“ trees are
great for
folks that
are far away.”
“Our “
em
html
body
“Main Menu”
div
p
em
“Our “
“breadth-rst”
a
“ trees are
a favorite
for nearby
neighbors.”
“You can
view other
products in
the ”
“.“
div
documentElement is a special property of the
document object. It always returns the root
element of the DOM tree.
Remember, the root element in
HTML is always <html>.