diff --git a/html/canvas/element/filters/2d.filter.drop-shadow-globalAlpha-expected.html b/html/canvas/element/filters/2d.filter.drop-shadow-globalAlpha-expected.html
new file mode 100644
index 00000000000000..bec81b2422ae67
--- /dev/null
+++ b/html/canvas/element/filters/2d.filter.drop-shadow-globalAlpha-expected.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<title>Canvas test: 2d.filter.drop-shadow-globalAlpha</title>
+<h1>2d.filter.drop-shadow-globalAlpha</h1>
+<p class="desc">Tests the context drop-shadow filter with a globalAlpha</p>
+<canvas id="canvas" width="100" height="50">
+  <p class="fallback">FAIL (fallback content)</p>
+</canvas>
+<script>
+  const canvas = document.getElementById("canvas");
+  const ctx = canvas.getContext('2d');
+
+  ctx.fillStyle = 'rgba(255, 165, 0, 0.5)';
+  ctx.fillRect(20, 15, 60, 30);
+  ctx.fillStyle = 'rgba(128, 0, 128, 0.5)'
+  ctx.fillRect(10, 10, 60, 30);
+</script>
diff --git a/html/canvas/element/filters/2d.filter.drop-shadow-globalAlpha.html b/html/canvas/element/filters/2d.filter.drop-shadow-globalAlpha.html
new file mode 100644
index 00000000000000..2a44537508647c
--- /dev/null
+++ b/html/canvas/element/filters/2d.filter.drop-shadow-globalAlpha.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<link rel="match" href="2d.filter.drop-shadow-globalAlpha-expected.html">
+<title>Canvas test: 2d.filter.drop-shadow-globalAlpha</title>
+<h1>2d.filter.drop-shadow-globalAlpha</h1>
+<p class="desc">Tests the context drop-shadow filter with a globalAlpha</p>
+<canvas id="canvas" width="100" height="50">
+  <p class="fallback">FAIL (fallback content)</p>
+</canvas>
+<script>
+  const canvas = document.getElementById("canvas");
+  const ctx = canvas.getContext('2d');
+
+  ctx.filter = 'drop-shadow(10px 5px 0px rgb(255, 165, 0))';
+  ctx.globalAlpha = 0.5
+  ctx.fillStyle = 'rgb(128, 0, 128)';
+  ctx.fillRect(10, 10, 60, 30);
+</script>
diff --git a/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha-expected.html b/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha-expected.html
new file mode 100644
index 00000000000000..bec81b2422ae67
--- /dev/null
+++ b/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha-expected.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<title>Canvas test: 2d.filter.drop-shadow-globalAlpha</title>
+<h1>2d.filter.drop-shadow-globalAlpha</h1>
+<p class="desc">Tests the context drop-shadow filter with a globalAlpha</p>
+<canvas id="canvas" width="100" height="50">
+  <p class="fallback">FAIL (fallback content)</p>
+</canvas>
+<script>
+  const canvas = document.getElementById("canvas");
+  const ctx = canvas.getContext('2d');
+
+  ctx.fillStyle = 'rgba(255, 165, 0, 0.5)';
+  ctx.fillRect(20, 15, 60, 30);
+  ctx.fillStyle = 'rgba(128, 0, 128, 0.5)'
+  ctx.fillRect(10, 10, 60, 30);
+</script>
diff --git a/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha.html b/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha.html
new file mode 100644
index 00000000000000..093b44c3d37aad
--- /dev/null
+++ b/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<link rel="match" href="2d.filter.drop-shadow-globalAlpha-expected.html">
+<title>Canvas test: 2d.filter.drop-shadow-globalAlpha</title>
+<h1>2d.filter.drop-shadow-globalAlpha</h1>
+<p class="desc">Tests the context drop-shadow filter with a globalAlpha</p>
+<canvas id="canvas" width="100" height="50">
+  <p class="fallback">FAIL (fallback content)</p>
+</canvas>
+<script>
+  const canvas = new OffscreenCanvas(100, 50);
+  const ctx = canvas.getContext('2d');
+
+  ctx.filter = 'drop-shadow(10px 5px 0px rgb(255, 165, 0))';
+  ctx.globalAlpha = 0.5
+  ctx.fillStyle = 'rgb(128, 0, 128)';
+  ctx.fillRect(10, 10, 60, 30);
+
+  const outputCanvas = document.getElementById("canvas");
+  outputCanvas.getContext('2d').drawImage(canvas, 0, 0);
+</script>
diff --git a/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha.w.html b/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha.w.html
new file mode 100644
index 00000000000000..dfec0e19fbaf90
--- /dev/null
+++ b/html/canvas/offscreen/filters/2d.filter.drop-shadow-globalAlpha.w.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<meta charset="UTF-8">
+<html class="reftest-wait">
+<link rel="match" href="2d.filter.drop-shadow-globalAlpha-expected.html">
+<title>Canvas test: 2d.filter.drop-shadow-globalAlpha</title>
+<h1>2d.filter.drop-shadow-globalAlpha</h1>
+<p class="desc">Tests the context drop-shadow filter with a globalAlpha</p>
+<canvas id="canvas" width="100" height="50">
+  <p class="fallback">FAIL (fallback content)</p>
+</canvas>
+<script id='myWorker' type='text/worker'>
+  self.onmessage = function(e) {
+    const canvas = new OffscreenCanvas(100, 50);
+    const ctx = canvas.getContext('2d');
+
+    ctx.filter = 'drop-shadow(10px 5px 0px rgb(255, 165, 0))';
+    ctx.globalAlpha = 0.5
+    ctx.fillStyle = 'rgb(128, 0, 128)';
+    ctx.fillRect(10, 10, 60, 30);
+
+    const bitmap = canvas.transferToImageBitmap();
+    self.postMessage(bitmap, bitmap);
+  };
+</script>
+<script>
+  const blob = new Blob([document.getElementById('myWorker').textContent]);
+  const worker = new Worker(URL.createObjectURL(blob));
+  worker.addEventListener('message', msg => {
+    const outputCtx = document.getElementById("canvas").getContext('2d');
+    outputCtx.drawImage(msg.data, 0, 0);
+    document.documentElement.classList.remove("reftest-wait");
+  });
+  worker.postMessage(null);
+</script>
+</html>
diff --git a/html/canvas/tools/yaml-new/filters.yaml b/html/canvas/tools/yaml-new/filters.yaml
index be28001fa73007..68c9dab7afd4d2 100644
--- a/html/canvas/tools/yaml-new/filters.yaml
+++ b/html/canvas/tools/yaml-new/filters.yaml
@@ -32,6 +32,19 @@
     ctx.filter = 'blur(  5px)';
     assert_equals(ctx.filter, 'blur(  5px)');
 
+- name: 2d.filter.drop-shadow-globalAlpha
+  desc: Tests the context drop-shadow filter with a globalAlpha
+  code: |
+    ctx.filter = 'drop-shadow(10px 5px 0px rgb(255, 165, 0))';
+    ctx.globalAlpha = 0.5
+    ctx.fillStyle = 'rgb(128, 0, 128)';
+    ctx.fillRect(10, 10, 60, 30);
+  reference: |
+    ctx.fillStyle = 'rgba(255, 165, 0, 0.5)';
+    ctx.fillRect(20, 15, 60, 30);
+    ctx.fillStyle = 'rgba(128, 0, 128, 0.5)'
+    ctx.fillRect(10, 10, 60, 30);
+
 - name: 2d.filter.canvasFilterObject.tentative
   desc: Test CanvasFilter() object
   canvas_types: ['HtmlCanvas']
