14.11 Creating Mixed Element and Text Nodes

NN 6, IE 5(Mac)/6(Win)

14.11.1 Problem

You want to generate content that consists of elements as well as text inside those elements.

14.11.2 Solution

Use the W3C DOM DocumentFragment object as an arbitrary container while assembling the content:

var frag, myEm, txt1, txt2;
frag = document.createDocumentFragment( );
myEm = document.createElement("em");
txt1 = document.createTextNode("very");
myEm .appendChild(txt1);
txt1 = document.createTextNode("I am ");
txt2 = document.createTextNode(" happy to see you.");
frag.appendChild(txt1);
frag.appendChild(myEm);
frag.appendChild(txt2);

At this point, the fragment (which starts and ends with text nodes) is ready for insertion or replacement at any existing element node in the document tree.

14.11.3 Discussion

Treat the DocumentFragment object like a scratch pad capable of containing any well-formed sequence of node types. The fragment exists solely in memory and is not a part of the document tree.

Internet Explorer implements the DocumentFragment object in Version 5 for the Macintosh and Version 6 or later for Windows. For earlier versions of Internet Explorer, there is no node-related equivalent. You can simulate the document fragment in memory by assembling element and text nodes in any generic container (such as a div or span). When it's time to place the content into the document tree, you can remove each child node of the temporary container, and append the removed node into the document's destination element. This is ugly, but possible.

Assembling mixed content, not as nodes but as strings, plays nicely in the innerHTML property of all elements (in IE 4 or later and NN 6 or later). The equivalent of the node approach just shown looks like the following:

var newContent = "I am <em>very</em> happy to see you.";

Then assign the new content to the innerHTML property of the desired element, which replaces the existing content with the new content.

The IE-only DOM equips elements with another method that assists insertion of strings containing text with or without HTML markup that is to be treated as renderable HTML. The insertAdjacentHTML( ) method (compatible back to IE 4) lets you determine where the insertion goes in relation to the element. The method takes two parameters. The first is a case-insensitive string signifying the relative location of the insertion point for the new content. Here are the four possible values for the first parameter:

BeforeBegin

In front of the start tag of the current element

AfterBegin

After the start tag, but immediately before any existing content of the current element

BeforeEnd

At the very end of the content of the element, just in front of the end tag

AfterEnd

After the end tag of the current element, but before any subsequent element

The new content is the second parameter. For example, to append the HTML string created earlier to an existing element whose ID is myP, the backward-compatible IE-only syntax is:

document.all("myP").insertAdjacentHTML("BeforeEnd", newContent);

Internet Explorer offers a large set of proprietary content manipulation methods, shown in Table 14-1.

Table 14-1. IE element content manipulation methods

Method	Compatibility	Description
contains(elemRef)	IE 4	Returns Boolean true if current element contains elemRef
getAdjacentText(where)	IE 5 (Win)	Returns text sequence from position where
insertAdjacentElement(where, elemRef)	IE 5 (Win)	Inserts new element object at position where
insertAdjacentHTML(where, HTMLText)	IE 4	Inserts text (at position where), which gets rendered as HTML
insertAdjacentText(where, text)	IE 4	Inserts text (at position where) as literal text
removeNode(deep)	IE 4	Deletes element or text node (and its child nodes if deep is true)
replaceAdjacentText(where, text)	IE 5 (Win)	Replaces current text at position where with text
replaceNode(newNodeRef)	IE 5 (Win)	Replace current node with new node
swapNode(otherNodeRef)	IE 5 (Win)	Exchange current node with otherNodeRef, and return reference to removed node

14.11.4 See Also

Recipe 14.9 for creating a new element; Recipe 14.10 for creating a new text node.