diff --git a/src/browser/canvas/WebGLRenderingContext.zig b/src/browser/canvas/WebGLRenderingContext.zig
index 4ededf49..688376c4 100644
--- a/src/browser/canvas/WebGLRenderingContext.zig
+++ b/src/browser/canvas/WebGLRenderingContext.zig
@@ -105,9 +105,17 @@ pub const Extension = union(enum) {
 
     /// Extension types.
     pub const Type = struct {
-        pub const WEBGL_debug_renderer_info = packed struct(u64) {
-            UNMASKED_RENDERER_WEBGL: u32 = 0,
-            UNMASKED_VENDOR_WEBGL: u32 = 0,
+        pub const WEBGL_debug_renderer_info = struct {
+            pub const UNMASKED_VENDOR_WEBGL: u64 = 0x9245;
+            pub const UNMASKED_RENDERER_WEBGL: u64 = 0x9246;
+
+            pub fn get_UNMASKED_VENDOR_WEBGL() u64 {
+                return UNMASKED_VENDOR_WEBGL;
+            }
+
+            pub fn get_UNMASKED_RENDERER_WEBGL() u64 {
+                return UNMASKED_RENDERER_WEBGL;
+            }
         };
     };
 };
diff --git a/src/tests/html/canvas.html b/src/tests/html/canvas.html
index dc900254..8c82d0e8 100644
--- a/src/tests/html/canvas.html
+++ b/src/tests/html/canvas.html
@@ -90,3 +90,16 @@
   }
 }
 </script>
+
+<script id=WebGLRenderingCanvas#getExtension>
+// WEBGL_debug_renderer_info
+{
+  const element = document.createElement("canvas");
+  const ctx = element.getContext("webgl");
+  const rendererInfo = ctx.getExtension("WEBGL_debug_renderer_info");
+  testing.expectEqual(true, rendererInfo instanceof WEBGL_debug_renderer_info);
+
+  testing.expectEqual(rendererInfo.UNMASKED_VENDOR_WEBGL, 0x9245);
+  testing.expectEqual(rendererInfo.UNMASKED_RENDERER_WEBGL, 0x9246);
+}
+</script>