I use element.style.height to change the element height but I found from docs that:

The following DOM properties are not supported in Prince 8.0:
element.style // supported in Prince 8.1

How can I else change element height with javascript or should I wait for prince 8.1 ?

The long way to do it is like this:

element.setAttribute("style", "height: 100px");

This will overwrite any existing style attribute, unfortunately. The style property will be supported in Prince 8.1, so you can just use:

element.style.height = "100px";