<svg xmlns="http://www.w3.org/2000/svg"
     xmlns:xlink="http://www.w3.org/1999/xlink"
     xmlns:h="http://www.w3.org/1999/xhtml" viewBox="0 0 4 4" width="200" height="200" class="reftest-wait">
  <metadata>
    <title>modifying xlink:href on an SVG image</title>
    <h:link rel="match" href="reference/green-rect-100x100.svg"/>
  </metadata>
  <script href="/common/reftest-wait.js"></script>
  <script href="/common/rendering-utils.js"></script>
  <image width="2" height="2" onload="test()"
         xlink:href="data:image/svg+xml,&lt;svg xmlns='http://www.w3.org/2000/svg' width='50' height='50' &gt;&lt;rect width='50' height='50' fill='red'/&gt;&lt;/svg&gt;"/>
  <script>
    const XLINK_NS = "http://www.w3.org/1999/xlink";
    const GREEN_DATA_URI = "data:image/svg+xml,&lt;svg xmlns='http://www.w3.org/2000/svg' width='50' height='50' &gt;&lt;rect width='50' height='50' fill='green'/&gt;&lt;/svg&gt;";

    // Our 'image' elem fires its load event more than once: first for the
    // initial data-URI, and then again after our dynamic mutation adjusts it.
    // But we only want test() to run for the first load, so we use
    // 'didStartTest' to nerf any invocations after the first.
    let didStartTest = false;
    async function test() {
      if (didStartTest) {
        return;
      }
      didStartTest = true;
      await waitForAtLeastOneFrame();
      document.querySelector('image').setAttributeNS(XLINK_NS, 'href',
                                                     GREEN_DATA_URI);
      await waitForAtLeastOneFrame();
      takeScreenshot();
    }
  </script>
</svg>