A DOMCursor object represents an ongoing operation over a list of results. It is an enhanced DOMRequest that allows to iterate through a list of results asynchronously. Each time its continue() method is called, the DOMCursor tries to reach the next result in the list and calls its result's success or error accordingly.
A DOMRequest object represents an ongoing operation. It provides callbacks that are called when the operation completes, as well as a reference to the operation's result. A DOM method that initiates an ongoing operation may return a DOMRequest object that you can use to monitor the progress of that operation.
The Element.attributes property returns a live collection of all attribute nodes registered to the specified node. It is a NamedNodeMap, not an Array, so it has no Array methods and the Attr nodes' indexes may differ among browsers. To be more specific, attributes is a key/value pair of strings that represents any information regarding that attribute.
getAttribute() returns the value of a specified attribute on the element. If the given attribute does not exist, the value returned will either be null or "" (the empty string); see Notes for details.
The Element.getElementsByTagName() method returns a live HTMLCollection of elements with the given tag name. The subtree underneath the specified element is searched, excluding the element itself. The returned list is live, meaning that it updates itself with the DOM tree automatically. Consequently, there is no need to call several times Element.getElementsByTagName() with the same element and arguments.