I try to get a sibling element with

element.nextElementSibling;

but it return undefined and not the (existing) element. Is nextElementSibling not supported by Prince?

For this I found a workaround with

var el = element.nextSibling;
		
while (el && el.nodeName != "DIV")
{
	el = el.nextSibling;
}

but now I have the next problem: The clientHeight property is also not supported and I have no idea, how can I determine the height of an element.

Any ideas?

It looks like we haven't added support for prev/nextElementSibling yet, we will add this to the roadmap.

Unfortunately it is not possible to get the width/height of elements from JavaScript, as all the scripts are executed before document layout is performed.

We have supported prev/nextElementSibling and other JavaScript DOM properties in Prince 11, available now. The clientHeight property and other size properties are still not supported unfortunately, although we do have a box tracking API which is available after layout has completed and can be used for some tasks.