<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
<svg width="450" height="450" xmlns="http://www.w3.org/2000/svg">
<defs>
    <linearGradient id="Gradient" gradientUnits="userSpaceOnUse" x1="10" y1="10" x2="440" y2="10">
        <stop id="stop1" stop-color="blue" offset="0"/>
        <stop stop-color="red" offset="1"/>
    </linearGradient>
</defs>

<rect x="10" y="10" width="430" height="80" fill="url(#Gradient)" />
<rect x="10" y="100" width="430" height="80" fill="url(#Gradient)" />

<script>
if (window.testRunnner)
    window.testRunner.waitUntilDone();

window.onload = () => {
    requestAnimationFrame(() => {
        document.getElementById("stop1").offset.baseVal = 0.3;
        if (window.testRunner)
            testRunner.notifyDone();
    });
}
</script>
</svg>