Question

Basically that’s the question, how is one supposed to construct a Document object from a string of HTML dynamically in javascript?

Answer 1

There are two methods defined in specifications, createDocument from DOM Core Level 2 and createHTMLDocument from HTML5. The former creates an XML document (including XHTML), the latter creates a HTML document. Both reside, as functions, on the DOMImplementation interface.

var impl    = document.implementation,
    xmlDoc  = impl.createDocument(namespaceURI, qualifiedNameStr, documentType),
    htmlDoc = impl.createHTMLDocument(title);

In reality, these methods are rather young and only implemented in recent browser releases. According to http://quirksmode.org and MDN, the following browsers support createHTMLDocument:

• Chrome 4
• Opera 10
• Firefox 4
• Internet Explorer 9
• Safari 4

Interestingly enough, you can (kind of) create a HTML document in older versions of Internet Explorer, using ActiveXObject:

var htmlDoc = new ActiveXObject("htmlfile");

The resulting object will be a new document, which can be manipulated just like any other document.