The "a" element is very similar to the "a" element in HTML. However, SMIL
also allows
the temporal behavior of the source when the link is followed to
be controlled.
The "show" attribute controls the behavior of the source containing
the link when the link is followed. It can have the following values:
"replace," which pauses the current presentation and replaces it by
the destination resource
"new," which starts the destination resource in a new context and does not
affect the source.
"pause," which pauses the source and starts the destination resource in a new
context -- when the destination resource ends, the source resumes
The "id" attribute gives a unique identifier to the element.
The "href" attribute specifies the URI of the link's destination.
The "a" element can have the following children: animation, audio, img, ref,
text, textstream, video, par, seq, switch.