SVGStopElement：offset 属性

<svg xmlns="http://www.w3.org/2000/svg" width="400" height="200">
  <defs>
    <linearGradient id="grad1" x1="0%" y1="0%" x2="100%" y2="100%">
      <stop offset="0%" stop-color="yellow" stop-opacity="1" />
      <stop offset="100%" stop-color="red" stop-opacity="1" />
    </linearGradient>
  </defs>
  <rect width="100%" height="100%" fill="url(#grad1)" />
</svg>

const stopElement = document.querySelector("stop");

// Access the offset property
console.log(stopElement.offset.baseVal); // Output: 0