SVGFEDropShadowElement: setStdDeviation() 方法

setStdDeviation(x, y)

<svg height="200" width="200" viewBox="0 0 200 200">
  <defs>
    <filter id="drop-shadow-filter">
      <feDropShadow
        in="SourceGraphic"
        dx="10"
        dy="10"
        stdDeviation="5 5"
        flood-color="gray" />
    </filter>
  </defs>

  <!-- Rectangle with an initial gray shadow -->
  <rect
    x="50"
    y="50"
    width="100"
    height="100"
    fill="red"
    filter="url(#drop-shadow-filter)" />
</svg>

<!-- Button to update the shadow -->
<button id="updateShadow" type="button">Update Shadow</button>

// Get the feDropShadow element
const dropShadow = document.querySelector("feDropShadow");

// Button to trigger the update
document.getElementById("updateShadow").addEventListener("click", () => {
  // Change the standard deviation (blur radius) of the shadow
  dropShadow.setStdDeviation(15, 20);
});