3 files changed, 10 insertions, 1 deletions
diff --git a/components/script/dom/webglprogram.rs b/components/script/dom/webglprogram.rs
index 543a551ee17..9ac3f4e1ad4 100644
--- a/components/script/dom/webglprogram.rs
+++ b/components/script/dom/webglprogram.rs
@@ -87,6 +87,10 @@ impl WebGLProgram {
         }
     }
 
+    pub fn is_deleted(&self) -> bool {
+        self.is_deleted.get()
+    }
+
     /// glLinkProgram
     pub fn link(&self) {
         self.linked.set(false);
diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index d20e55429c4..5ff793527ec 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -1403,6 +1403,11 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         frame_buffer.map_or(false, |buf| buf.target().is_some() && !buf.is_deleted())
     }
 
+    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
+    fn IsProgram(&self, program: Option<&WebGLProgram>) -> bool {
+        program.map_or(false, |p| !p.is_deleted())
+    }
+
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.7
     fn IsRenderbuffer(&self, render_buffer: Option<&WebGLRenderbuffer>) -> bool {
         render_buffer.map_or(false, |buf| buf.ever_bound() && !buf.is_deleted())
diff --git a/components/script/dom/webidls/WebGLRenderingContext.webidl b/components/script/dom/webidls/WebGLRenderingContext.webidl
index eea550a5bc0..e95ce00e5e5 100644
--- a/components/script/dom/webidls/WebGLRenderingContext.webidl
+++ b/components/script/dom/webidls/WebGLRenderingContext.webidl
@@ -605,7 +605,7 @@ interface WebGLRenderingContextBase
     [WebGLHandlesContextLoss] GLboolean isBuffer(WebGLBuffer? buffer);
     //[WebGLHandlesContextLoss] GLboolean isEnabled(GLenum cap);
     [WebGLHandlesContextLoss] GLboolean isFramebuffer(WebGLFramebuffer? framebuffer);
-    //[WebGLHandlesContextLoss] GLboolean isProgram(WebGLProgram? program);
+    [WebGLHandlesContextLoss] GLboolean isProgram(WebGLProgram? program);
     [WebGLHandlesContextLoss] GLboolean isRenderbuffer(WebGLRenderbuffer? renderbuffer);
     [WebGLHandlesContextLoss] GLboolean isShader(WebGLShader? shader);
     [WebGLHandlesContextLoss] GLboolean isTexture(WebGLTexture? texture);