DOMParser

The DOMParser interface provides the ability to parse XML or HTML source code from a string into a DOM Document.

You can perform the opposite operation—converting a DOM tree into XML or HTML source—using the XMLSerializer interface.

In the case of an HTML document, you can also replace portions of the DOM with new DOM trees built from HTML by setting the value of the Element.innerHTML and outerHTML properties. These properties can also be read to fetch HTML fragments corresponding to the corresponding DOM subtree.

Note that XMLHttpRequest can parse XML and HTML directly from a URL-addressable resource, returning a Document in its response property.