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13.6.2.5 Document Objects

A `Document` represents an entire XML document, including its constituent elements, attributes, processing instructions, comments etc. Remeber that it inherits properties from `Node`.

`documentElement`
  The one and only root element of the document.

`createElement`(tagName)
  Create and return a new element node. The element is not inserted into the document when it is created. You need to explicitly insert it with one of the other methods such as `insertBefore()` or `appendChild()`.

`createElementNS`(namespaceURI, tagName)
  Create and return a new element with a namespace. The tagName may have a prefix. The element is not inserted into the document when it is created. You need to explicitly insert it with one of the other methods such as `insertBefore()` or `appendChild()`.

`createTextNode`(data)
  Create and return a text node containing the data passed as a parameter. As with the other creation methods, this one does not insert the node into the tree.

`createComment`(data)
  Create and return a comment node containing the data passed as a parameter. As with the other creation methods, this one does not insert the node into the tree.

`createProcessingInstruction`(target, data)
  Create and return a processing instruction node containing the target and data passed as parameters. As with the other creation methods, this one does not insert the node into the tree.

`createAttribute`(name)
  Create and return an attribute node. This method does not associate the attribute node with any particular element. You must use `setAttributeNode()` on the appropriate `Element` object to use the newly created attribute instance.

`createAttributeNS`(namespaceURI, qualifiedName)
  Create and return an attribute node with a namespace. The tagName may have a prefix. This method does not associate the attribute node with any particular element. You must use `setAttributeNode()` on the appropriate `Element` object to use the newly created attribute instance.

`getElementsByTagName`(tagName)
  Search for all descendants (direct children, children's children, etc.) with a particular element type name.

`getElementsByTagNameNS`(namespaceURI, localName)
  Search for all descendants (direct children, children's children, etc.) with a particular namespace URI and localname. The localname is the part of the namespace after the prefix.