diff --git a/pkg/test_runner/lib/src/browser_controller.dart b/pkg/test_runner/lib/src/browser_controller.dart
index 4c3ab8bd29c..b0e400cdf29 100644
--- a/pkg/test_runner/lib/src/browser_controller.dart
+++ b/pkg/test_runner/lib/src/browser_controller.dart
@@ -1388,12 +1388,15 @@ body div {
         test_completed = false;
       }
 
-      window.onerror = function (message, url, lineNumber) {
-        if (url) {
-          reportError(url + ':' + lineNumber + ':' + message);
-        } else {
-          reportError(message);
+      window.onerror = function (message, url, lineNumber, columnNumber, err) {
+        // Ensure the stack is included in the reported error, if available.
+        if (err && err.stack) {
+          message = message + '\\n' + err.stack;
         }
+        if (url) {
+          message = url + ':' + lineNumber + ':' + columnNumber + ':' + message;
+        }
+        reportError(message);
       }
 
       function reportError(msg) {
diff --git a/pkg/test_runner/lib/src/test_controller.js b/pkg/test_runner/lib/src/test_controller.js
index e7523427904..caaf894b3b4 100644
--- a/pkg/test_runner/lib/src/test_controller.js
+++ b/pkg/test_runner/lib/src/test_controller.js
@@ -93,10 +93,14 @@ var hadTopLevelError = false;
 
 // Set window onerror to make sure that we catch test harness errors across all
 // browsers.
-window.onerror = function (message, url, lineNumber) {
+window.onerror = function (message, url, lineNumber, columnNumber, err) {
+  // Ensure the stack is included in the reported error, if available.
+  if (err && err.stack) {
+    message = message + '\n' + err.stack;
+  }
   if (url) {
     message = ('window.onerror called: \n\n' +
-        url + ':' + lineNumber + ':\n' + message + '\n\n');
+        url + ':' + lineNumber + ':' + columnNumber + ':\n' + message + '\n\n');
   }
   if (testExpectsGlobalError) {
     testSuppressedGlobalErrors.push({