第337页 The Text Type

nodeType is 3.
nodeName is “#text”.
nodeValue is text contained in the node.
parentNode is an Element.
Child nodes are not supported.

appendData(text) — Appends text to the end of the node.
deleteData(offset, count) — Deletes count number of characters starting at position offset.
insertData(offset, text) — Inserts text at position offset.
replaceData(offset, count, text) — Replaces the text starting at offset through offset + count with text.
splitText(offset) — Splits the text node into two text nodes separated at position offset.
substringData(offset, count) — Extracts a string from the text beginning at position offset and continuing until offset + count.

<!-- no content, so no text node -->
<div></div>     
                    
<!-- white space content, so one text node -->
<div> </div>     
                    
<!-- content, so one text node -->
<div>Hello World!</div>

检索：var textNode = div.firstChild;  //or div.childNodes[0]
更改：div.firstChild.nodeValue = “Some other message”;

//outputs as “Some &lt;strong&gt;other&lt;/strong&gt; message”
div.firstChild.nodeValue = “Some <strong>other</strong> message”;

Creating Text Nodes
 document.createTextNode()

var textNode = document.createTextNode(“<strong>Hello</strong> world!”);

var element = document.createElement(“div”);
element.className = “message”;
                    
var textNode = document.createTextNode(“Hello world!”);
element.appendChild(textNode);
                    
document.body.appendChild(element);