opacity

The opacity attribute specifies the transparency of an object or of a group of objects, that is, the degree to which the background behind the element is overlaid.

Note: As a presentation attribute, opacity can be used as a CSS property. See the css opacity property for more information.

As a presentation attribute, it can be applied to any element but it has effect only on the following elements: <a>, <audio>, <canvas>, <circle>, <ellipse>, <foreignObject>, <g>, <iframe>, <image>, <line>, <marker>, <path>, <polygon>, <polyline>, <rect>, <svg>, <switch>, <symbol>, <text>, <textPath>, <tspan>, <use>, <unknown>, and <video>

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

<svg viewBox="0 0 200 100" xmlns="http://www.w3.org/2000/svg">
  <defs>
    <linearGradient id="gradient" x1="0%" y1="0%" x2="0" y2="100%">
      <stop offset="0%" style="stop-color:skyblue;" />
      <stop offset="100%" style="stop-color:seagreen;" />
    </linearGradient>
  </defs>
  <rect x="0" y="0" width="100%" height="100%" fill="url(#gradient)" />
  <circle cx="50" cy="50" r="40" fill="black" />
  <circle cx="150" cy="50" r="40" fill="black" opacity="0.3" />
</svg>

Usage notes

<alpha-value>

The uniform opacity setting to be applied across an entire object, as a <number>. Any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) will be clamped to this range.

Specifications

Browser compatibility

See also

• css opacity