JS/CSS style.transition

[SigmaTec]

it's about creating a graphic animation of a rolling shutter that opens and closes...
If you have it easier with CSS and changes of properties with JS, I'm interested!

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I tested olso :

CSS :
.testVR {
transition = 'height 2s linear 1s';
}

2nd WAY for transition attribute in JS :
elem[0].style.setProperty("transition", "height 2s linear 0s");

But they doesn't work any more.