JavaScript 2.0-The Complete Reference, Second ... - freecodingtutorial

This paragraph has an em element in it.
Because of the fact that Opera and Mozilla-based browsers include white space in their DOM
tree, you may notice that you have to press the Delete button a few more times in the preceding
example to effect the same change as you would in IE. Despite the DOM being standard, we
see that a subtle difference in interpretation of the standard can have significant consequences.
Modifying Nodes
Elements really cannot be directly modified, although their attributes certainly can. This may
seem strange, but it makes perfect sense when you consider that elements contain text nodes.
To effect a change, you really have to modify the text nodes themselves. For example, if you
had
This is a test
you would use
textNode = document.getElementById('p1').firstChild;
to access the text node ―This is a test‖ within the paragraph element. Notice how we strung
together the firstChild property with the method call. Experienced DOM programmers find that
stringing methods and properties together like this helps avoid having to use numerous
individual statements to access a particular item. Once the textNode has been retrieved we
could access its length using its length property (which indicates the number of characters it
contains), or even set its value using the data property.
alert(textNode.length); // would return 14
textNode.data = "I've been changed!";
DOM Level 1 also defines numerous methods to operate on text nodes. These are summarized
in Table 10-5.