Default is false. Opening all the media elements at the beginning of the presentation can take considerable time and memory, so we recommend that it be done only for simple presentations with a few small media elements. When used in an element tag, specifies that this particular element should be downloaded or streamed as soon as the presentation is opened. You might use this to preload an element to be sure it is already in memory when it needs to play. Possible values are character strings matching a valid MIME type.
Possible targets are an existing browser window, a browser frame, or quicktimeplayer.
If the target string is none of these, a new browser window is created. During a SMIL presentation, QuickTime dynamically loads media elements as required, so the known duration of the overall presentation can change as a movie is played or navigated. When the known duration changes, the scale of the Time slider changes to reflect that. This can be confusing to the viewer. Because of this, QuickTime movies created from SMIL documents do not normally display a Time slider.