files/en-us/web/api/svgmarkerelement/markerwidth/index.md
{{APIRef("SVG")}}
The markerWidth read-only property of the {{domxref("SVGMarkerElement")}} interface returns an {{domxref("SVGAnimatedLength")}} object containing the width of the {{SVGElement("marker")}} viewport as defined by the {{SVGattr("markerWidth")}} attribute.
An {{domxref("SVGAnimatedLength")}} object. The baseVal property of this object returns an {{domxref("SVGLength")}}, the value of which returns the width.
The markerWidth property returns an {{domxref("SVGAnimatedLength")}} which contains an {{domxref("SVGLength")}} with the value of the {{SVGattr("markerWidth")}} 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">
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
</defs>
</svg>
let marker = document.getElementById("arrow");
console.log(marker.markerWidth.baseVal.value); // 6
{{Specifications}}
{{Compat}}