SVG 1.2 - 27 October 2004
The SVG working group is considering streaming enhancements to the SVG language. Here are two identified uses for streaming:
To meet the requirements of these use cases, SVG 1.2 adds a method to mark streamed content as available for discard and a method to control the start of an element's local time.
The timelineBegin attribute controls the initialization of the timeline on a time container.
timelineBegin = "onLoad" | "onStart"
For streaming animations, the author would typically set the root svg element, which controls the global timeline, to "onStart", thus allowing the nested timelines to begin as the document arrives. The page elements, which normally represent scenes in the animation, typically use the default value of "onLoad", ensuring that the entire scene is loaded before the nested timeline begins.
The timelineBegin attribute only affects time containers.
The streamedContents attribute allows an author to mark the contents of a document as unnecessary. It is allowed on the root svg element.
streamedContents = "keep" | "discard"
In effect, this attribute controls whether or not a user agent is able to discard the contents of the page elements that have already been displayed.