Next button in symbol, start animation from the timeline and after 3 sec playReverse

Hello,

I have a next button in a symbol. When I click on the button I would like to start the animation from the timeline.

It wil starts at one second. But if the timeline is after 3 seconds I would like to play the animation backwards (if you click on the same button).

I tried it with the code below but it starts always at 1 second.

var pos = sym.getPosition() //

if (pos <= '1000'){

         sym.getComposition().getStage().play(1001);

}

else if (pos <= '3000'){

          sym.getComposition().getStage().playReverse(2999);

}

Can anybody help me with the code?

Thanks!