The height read-only property of the SVGFECompositeElement interface describes the vertical size of an SVG filter primitive as a SVGAnimatedLength.
It reflects the <feComposite> element's height filter primitive attribute. The <feComposite> SVG filter primitive combines two input images using a Porter-Duff compositing operation. The attribute is a <length> or a <percentage> relative to the height of the filter region. The default value is 100%. The property value is a length in user coordinate system units.
const feComposite = document.querySelector("feComposite");
const verticalSize = feComposite.height;
console.log(verticalSize.baseVal.value); // the `height` valueSVGFECompositeElement.width<blend-mode> data typemix-blend-mode property