SVG animation begin at wallclock-sync-value

SVG spec by w3c defines wallclock-sync-value as a possible value for "begin" attribute ( http://www.w3.org/TR/SVG/animate.html#WallclockSyncValueSyntax ).
In other words: start animation based on real clock time, not based on times relative to document loading.

I want to create a SVG clock in a situation, where scripting is disabled.

I failed to find any examples of the wallclock usage, but based on the spec and ISO8601 ( http://en.wikipedia.org/wiki/ISO_8601 ) I made following excample:

<text 
  x="0" 
  y="15" 
  opacity="0" >

    <animate 
      attributeName="opacity" 
      attributeType="XML" 
      begin="wallclock(2000-01-01T00:00:00Z)" 
      dur="10s" 
      values="1; 1; 0; 0" 
      keyTimes="0; 0.07; 0.1; 1" 
      repeatCount="indefinite" />
  0
</text>

That should be the rightmost "0" digit in a digital clock, and should flicr every 10 secconds. It works when I set begin="0s".

Unfortunately it does not work as expected. For example in Firefox developer console it gives a js warning(!?!) "Unexpected value wallclock(2000-01-01T00:00:00Z) parsing begin attribute."

Is wallclock-sync-value implemented in modern browsers, and how to use it?

Solution

Firefox doesn't currently implement wallclock and won't be implementing it in the future either.

We expect it to disappear and be replaced by something else in SVG 2. I believe the developers of the other UAs are of a similar opinion.