diff --git a/fetch.js b/fetch.js
index eaa08ceda5203f6cd3475eeb07e8b3214648c286..ed70f1c42a2553d98fe559616209333c0b536639 100644
--- a/fetch.js
+++ b/fetch.js
@@ -76,9 +76,20 @@
       throw new Error('Not implemented yet')
     }
 
-    this.blob = function() {
-      var rejected = consumed(this)
-      return rejected ? rejected : Promise.resolve(new Blob([this._body]))
+    var blobSupport = (function() {
+      try {
+        new Blob();
+        return true
+      } catch(e) {
+        return false
+      }
+    })();
+
+    if (blobSupport) {
+      this.blob = function() {
+        var rejected = consumed(this)
+        return rejected ? rejected : Promise.resolve(new Blob([this._body]))
+      }
     }
 
     this.formData = function() {
diff --git a/test/.jshintrc b/test/.jshintrc
index 8202adff1c1c8b0901be55fed675e0388eaa9206..45ba1e95270fabe35cf2f1a620a30b261207ae38 100644
--- a/test/.jshintrc
+++ b/test/.jshintrc
@@ -21,6 +21,9 @@
     "MockXHR": false,
     "QUnit": false,
     "fetch": false,
+    "Headers": false,
+    "Request": false,
+    "Response": false,
     "module": false,
     "test": false,
     "asyncTest": false,
diff --git a/test/test.js b/test/test.js
index 40f89da60989f378d730adee61cea2a88a4b7457..f17e6f7837c7475bba90fd2e9f0f59a4759dd1ec 100644
--- a/test/test.js
+++ b/test/test.js
@@ -1,12 +1,3 @@
-var blobSupport = (function() {
-  try {
-    new Blob();
-    return true
-  } catch(e) {
-    return false
-  }
-})();
-
 promiseTest('populates response body', 2, function() {
   return fetch('/hello').then(function(response) {
     equal(response.status, 200)
@@ -72,13 +63,15 @@ promiseTest('resolves text promise', 1, function() {
   })
 })
 
-promiseTest('parses form encoded response', 1, function() {
-  return fetch('/form').then(function(response) {
-    return response.formData()
-  }).then(function(form) {
-    ok(form instanceof FormData, 'Parsed a FormData object')
+if (Response.prototype.formData) {
+  promiseTest('parses form encoded response', 1, function() {
+    return fetch('/form').then(function(response) {
+      return response.formData()
+    }).then(function(form) {
+      ok(form instanceof FormData, 'Parsed a FormData object')
+    })
   })
-})
+}
 
 promiseTest('parses json response', 2, function() {
   return fetch('/json').then(function(response) {
@@ -98,7 +91,7 @@ promiseTest('handles json parse error', 2, function() {
   })
 })
 
-if (blobSupport) {
+if (Response.prototype.blob) {
   promiseTest('resolves blob promise', 2, function() {
     return fetch('/hello').then(function(response) {
       return response.blob()
@@ -121,7 +114,7 @@ promiseTest('post sets content-type header', 2, function() {
   })
 })
 
-if (blobSupport) {
+if (Response.prototype.blob) {
   promiseTest('rejects blob promise after body is consumed', 2, function() {
     return fetch('/hello').then(function(response) {
       ok(response.blob, 'Body does not implement blob')
@@ -153,15 +146,17 @@ promiseTest('rejects text promise after body is consumed', 2, function() {
   })
 })
 
-promiseTest('rejects formData promise after body is consumed', 2, function() {
-  return fetch('/json').then(function(response) {
-    ok(response.formData, 'Body does not implement formData')
-    response.formData()
-    return response.formData()
-  }).catch(function(error) {
-    ok(error instanceof TypeError, 'Promise rejected after body consumed')
+if (Response.prototype.formData) {
+  promiseTest('rejects formData promise after body is consumed', 2, function() {
+    return fetch('/json').then(function(response) {
+      ok(response.formData, 'Body does not implement formData')
+      response.formData()
+      return response.formData()
+    }).catch(function(error) {
+      ok(error instanceof TypeError, 'Promise rejected after body consumed')
+    })
   })
-})
+}
 
 promiseTest('supports HTTP PUT', 2, function() {
   return fetch('/request', {