Creating, Inserting, and Deleting Nodes

We’ve seen how to query and alter document content using strings of HTML and of plain text. And we’ve also seen that we can traverse a Document to examine the individual Element and Text nodes that it is made of. It is also possible to alter a document at the level of individual nodes. The Document type defines methods for creating Element and Text objects, and the Node type defines methods for inserting, deleting, and replacing nodes in the tree. Example 13-4 demonstrated both node creation and node insertion, and that short example is duplicated here:

// Asynchronously load and execute a script from a specified URL
function loadasync(url) { 
    var head = document.getElementsByTagName("head")[0]; // Find document <head>
    var s = document.createElement("script");  // Create a <script> element
    s.src = url;                               // Set its src attribute 
    head.appendChild(s);                       // Insert the <script> into head

The subsections that follow include more details and examples of node creation, of the insertion and deletion of nodes, and also of the use of DocumentFragment as a shortcut when working with multiple nodes.

Creating Nodes

As shown in the code above, you can create new Element nodes with the createElement() method of the Document object. Pass the tag name of the element as the method argument: this name is case-insensitive for HTML documents and case-sensitive for XML documents.

Text nodes are created with a similar method:

var newnode = document.createTextNode("text node ...

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