marker-start

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨July 2020⁩.

The marker-start attribute defines the arrowhead or polymarker that will be drawn at the first vertex of the given shape.

For all shape elements, except <polyline> and <path>, the last vertex is the same as the first vertex. In this case, if the value of marker-start and marker-end are both not none, then two markers will be rendered on that final vertex. For <path> elements, for each closed subpath, the last vertex is the same as the first vertex. marker-start is only rendered on the first vertex of the path data.

Note: As a presentation attribute, marker-start also has a CSS property counterpart: marker-start. When both are specified, the CSS property takes priority.

You can use this attribute with the following SVG elements:

Example

html,
body,
svg {
  height: 100%;
}

html

<svg viewBox="0 0 120 120" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <marker
      id="triangle"
      viewBox="0 0 10 10"
      refX="1"
      refY="5"
      markerUnits="strokeWidth"
      markerWidth="10"
      markerHeight="10"
      orient="auto">
      <path d="M 0 0 L 10 5 L 0 10 z" fill="red" />
    </marker>
  </defs>
  <polyline
    fill="none"
    stroke="black"
    points="20,100 40,60 70,80 100,20"
    marker-start="url(#triangle)" />
</svg>

Usage notes

Value	`none` \| `<marker-ref>`
Default value	`none`
Animatable	discrete

none: Indicates that no marker symbol shall be drawn at the first vertex.
<marker-ref>: This value is a reference to a <marker> element, which will be drawn at the first vertex. If the reference is not valid, then no marker will be drawn.