When looking through the docs, remember that many classes extend others (e.g. DOMElement extends from DOMNode) and not all of them list all of the inherited properties and/or methods (and those that do, generally only show the members inherited from their immediate parent class).
With regard to your question, as Anthony mentioned, there is the nodeValue property which gives the node’s value (what that is, varies depending on the node) and there is also the textContent which contains the text content of the node and its descendants.