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removeChild

You’re not done quite yet. You have created the element and text node and attached them to each other,

but the element still doesn’t have a spot in the document. To actually be visible, the element must be

attached either to the

document.body

element or one of its children. Once again, you can use the

appendChild()

method for this:

document.body.appendChild(oP);

To put all this into a sample you can run, just create a function containing each of these steps and call it

when the page is loaded by using the

onload

event handler (events will be covered in more detail in the

Chapter 9, “All About Events”):

<html>

<head>

<title>createElement() Example</title>

function createMessage() {

var oP = document.createElement(“p”);

var oText = document.createTextNode(“Hello World! “);

oP.appendChild(oText);

document.body.appendChild(oP);

}

</script>

</head>

</body>

</html>

When you run this code, the message

“Hello World!”

is displayed as if it were part of the HTML doc-

ument all along.

removeChild(), replaceChild(), and insertBefore()

Naturally, if you can add a node you can also remove a node, which is where the

removeChild()

method comes in. This method accepts one argument, the node to remove, and then returns that node as

the function value. So if, for instance, you start out with a page already containing the

“Hello World!”

message and you wanted to remove it, you can use the method like this:

<html>

<head>

<title>removeChild() Example</title>

function removeMessage() {

var oP = document.body.getElementsByTagName(“p”)[0];

At this point, it’s prudent to point out that all DOM manipulation must occur after

the page has fully loaded. It isn’t possible to insert code while a page is loading to

work with the DOM because the DOM tree isn’t fully constructed until the page has

been completely downloaded to the client machine. For this reason, all code must be

executed using the

onload

event handler.

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DOM Basics

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