chromium/third_party/blink/web_tests/svg/custom/evt-onload.svg

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" onload="test(evt)">
<script>
function test(evt) {
    if (evt)
        document.getElementById("rect").setAttribute("fill", "green");
}
</script>
<rect id="rect" width="100" height="100" fill="red"/>
</svg>