files/en-us/web/api/svgmarkerelement/markerunits/index.md
{{APIRef("SVG")}}
The markerUnits read-only property of the {{domxref("SVGMarkerElement")}} interface returns an {{domxref("SVGAnimatedEnumeration")}} object. This object returns an integer which represents the keyword values that the {{SVGattr("markerUnits")}} attribute accepts.
An {{domxref("SVGAnimatedEnumeration")}} object. The baseVal property of this object contains one of the following values:
0
SVG_MARKERUNITS_UNKNOWN which means that the {{SVGattr("markerUnits")}} attribute has a value other than the two predefined keywords.1
SVG_MARKERUNITS_USERSPACEONUSE which means that the {{SVGattr("markerUnits")}} attribute has the keyword value userSpaceOnUse.2
SVG_MARKERUNITS_STROKEWIDTH which means that the {{SVGattr("markerUnits")}} attribute has the keyword value strokeWidth.The markerUnits property returns an {{domxref("SVGAnimatedEnumeration")}} object that contains the value of the {{SVGattr("markerUnits")}} attribute.
<svg id="svg" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
<defs>
<marker
id="arrow"
viewBox="0 0 10 10"
refX="5"
refY="5"
markerWidth="6"
markerHeight="6"
orient="auto-start-reverse"
markerUnits="strokeWidth">
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
</defs>
</svg>
let marker = document.getElementById("arrow");
console.log(marker.markerUnits.baseVal); // 2
{{Specifications}}
{{Compat}}