diff --git a/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/remote-experiment-loader.js b/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/remote-experiment-loader.js
index b736dad1ebff..0599d4a0a02d 100644
--- a/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/remote-experiment-loader.js
+++ b/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/remote-experiment-loader.js
@@ -132,7 +132,7 @@ function downloadFile(url, cb, lastModified) {
     console.info("Using binary mode to download jar file.");
     req.overrideMimeType('text/plain; charset=x-user-defined');
   }
-  req.onreadystatechange = function(aEvt) {
+  req.addEventListener("readystatechange", function(aEvt) {
     if (req.readyState == 4) {
       if (req.status == 200) {
         // check security channel:
@@ -154,7 +154,7 @@ function downloadFile(url, cb, lastModified) {
 	cb(null);
       }
     }
-  };
+  }, false);
   req.send();
 }
 
diff --git a/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/tasks.js b/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/tasks.js
index cb6775ac3887..684948a41bd9 100644
--- a/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/tasks.js
+++ b/browser/app/profile/extensions/testpilot@labs.mozilla.com/modules/tasks.js
@@ -846,7 +846,7 @@ TestPilotExperiment.prototype = {
       req.setRequestHeader("Content-type", "application/json");
       req.setRequestHeader("Content-length", dataString.length);
       req.setRequestHeader("Connection", "close");
-      req.onreadystatechange = function(aEvt) {
+      req.addEventListener("readystatechange", function(aEvt) {
         if (req.readyState == 4) {
           if (req.status == 200 || req.status == 201 || req.status == 202) {
             let location = req.getResponseHeader("Location");
@@ -887,7 +887,7 @@ TestPilotExperiment.prototype = {
             callback(false);
           }
         }
-      };
+      }, false);
       req.send(dataString);
     });
   },
@@ -919,7 +919,7 @@ TestPilotExperiment.prototype = {
       req.setRequestHeader("Content-type", "application/json");
       req.setRequestHeader("Content-length", dataString.length);
       req.setRequestHeader("Connection", "close");
-      req.onreadystatechange = function(aEvt) {
+      req.addEventListener("readystatechange", function(aEvt) {
         if (req.readyState == 4) {
           if (req.status == 200 || req.status == 201 || req.status == 202) {
 	    logger.info("Quit reason posted successfully " + req.responseText);
@@ -933,7 +933,7 @@ TestPilotExperiment.prototype = {
             }
 	  }
 	}
-      };
+      }, false);
       logger.trace("Sending quit reason.");
       req.send(dataString);
     } else {
@@ -1069,7 +1069,7 @@ TestPilotBuiltinSurvey.prototype = {
       req.setRequestHeader("Content-type", "application/json");
       req.setRequestHeader("Content-length", params.length);
       req.setRequestHeader("Connection", "close");
-      req.onreadystatechange = function(aEvt) {
+      req.addEventListener("readystatechange", function(aEvt) {
         if (req.readyState == 4) {
           if (req.status == 200 || req.status == 201 ||
              req.status == 202) {
@@ -1099,7 +1099,7 @@ TestPilotBuiltinSurvey.prototype = {
 	    callback(false);
 	  }
         }
-      };
+      }, false);
       req.send(params);
     });
   }
diff --git a/build/win32/crashinject.cpp b/build/win32/crashinject.cpp
index 10e64273016e..cc089735383e 100644
--- a/build/win32/crashinject.cpp
+++ b/build/win32/crashinject.cpp
@@ -71,7 +71,7 @@ int main(int argc, char** argv)
   wcscpy(slash, L"crashinjectdll.dll");
 
   // now find our target process
-  HANDLE targetProc = OpenProcess(PROCESS_VM_OPERATION | PROCESS_VM_WRITE | PROCESS_CREATE_THREAD,
+  HANDLE targetProc = OpenProcess(PROCESS_VM_OPERATION | PROCESS_VM_WRITE | PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION,
                                   FALSE,
                                   pid);
   if (targetProc == NULL) {
diff --git a/content/base/src/FileIOObject.cpp b/content/base/src/FileIOObject.cpp
index af70ca09423d..cfa07bcfa757 100644
--- a/content/base/src/FileIOObject.cpp
+++ b/content/base/src/FileIOObject.cpp
@@ -43,6 +43,7 @@
 #include "nsIDOMProgressEvent.h"
 #include "nsComponentManagerUtils.h"
 #include "nsEventDispatcher.h"
+#include "xpcprivate.h"
 
 #define ERROR_STR "error"
 #define ABORT_STR "abort"
diff --git a/content/base/src/nsDOMFileReader.cpp b/content/base/src/nsDOMFileReader.cpp
index ffe992cdb7e2..5b4c1799dcc1 100644
--- a/content/base/src/nsDOMFileReader.cpp
+++ b/content/base/src/nsDOMFileReader.cpp
@@ -77,7 +77,8 @@
 #include "nsIScriptObjectPrincipal.h"
 #include "nsFileDataProtocolHandler.h"
 #include "mozilla/Preferences.h"
-#include "xpcprivate.h" 	
+#include "xpcprivate.h"
+#include "xpcpublic.h"
 #include "xpcquickstubs.h"
 #include "jstypedarray.h"
 
diff --git a/content/base/src/nsEventSource.cpp b/content/base/src/nsEventSource.cpp
index 7bcb5d3aaa9c..6be83536da16 100644
--- a/content/base/src/nsEventSource.cpp
+++ b/content/base/src/nsEventSource.cpp
@@ -59,6 +59,7 @@
 #include "nsIContentSecurityPolicy.h"
 #include "nsContentUtils.h"
 #include "mozilla/Preferences.h"
+#include "xpcpublic.h"
 
 using namespace mozilla;
 
diff --git a/content/base/src/nsWebSocket.cpp b/content/base/src/nsWebSocket.cpp
index 12ab15edc9a2..7268c138f129 100644
--- a/content/base/src/nsWebSocket.cpp
+++ b/content/base/src/nsWebSocket.cpp
@@ -78,6 +78,7 @@
 #include "nsIRequest.h"
 #include "mozilla/Preferences.h"
 #include "nsDOMLists.h"
+#include "xpcpublic.h"
 
 using namespace mozilla;
 
diff --git a/content/base/test/unit/test_bug553888.js b/content/base/test/unit/test_bug553888.js
index 9433f7a8aba3..60cdf77d386e 100644
--- a/content/base/test/unit/test_bug553888.js
+++ b/content/base/test/unit/test_bug553888.js
@@ -79,12 +79,12 @@ function run_test() {
                 .createInstance(Components.interfaces.nsIXMLHttpRequest);
   request.open("GET", redirectURL, true);
   request.setRequestHeader("X-Custom-Header", "present");
-  request.onreadystatechange = function() {
+  request.addEventListener("readystatechange", function() {
     if (request.readyState == 4) {
       do_check_eq(request.status, 200);
       server.stop(do_test_finished);
     }
-  };
+  }, false);
   request.send();
   try {
     request.setRequestHeader("X-Unwanted-Header", "present");
diff --git a/content/base/test/unit/test_error_codes.js b/content/base/test/unit/test_error_codes.js
index 35528bb1a399..c8e2da29459d 100644
--- a/content/base/test/unit/test_error_codes.js
+++ b/content/base/test/unit/test_error_codes.js
@@ -46,7 +46,7 @@ var asyncXHR = {
     request.open("GET", "http://localhost:4444/test_error_code.xml", true);
 
     var self = this;
-    request.onerror = function(event) { self.onError(event); };
+    request.addEventListener("error", function(event) { self.onError(event); }, false);
     request.send(null);
   },
   onError: function doAsyncRequest_onError(event) {
diff --git a/dom/system/NetworkGeolocationProvider.js b/dom/system/NetworkGeolocationProvider.js
index 14c919b09ef8..9c0361c3a4b4 100755
--- a/dom/system/NetworkGeolocationProvider.js
+++ b/dom/system/NetworkGeolocationProvider.js
@@ -239,10 +239,10 @@ WifiGeoPositionProvider.prototype = {
     xhr.mozBackgroundRequest = true;
     xhr.open("GET", providerUrl, false);
     xhr.channel.loadFlags = Ci.nsIChannel.LOAD_ANONYMOUS;
-    xhr.onerror = function(req) {
+    xhr.addEventListener("error", function(req) {
         LOG("onerror: " + req);
-    };
-    xhr.onload = function (req) {  
+    }, false);
+    xhr.addEventListener("load", function (req) {  
         LOG("service returned: " + req.target.responseText);
         response = JSON.parse(req.target.responseText);
         /*
@@ -288,7 +288,7 @@ WifiGeoPositionProvider.prototype = {
               }
           }
         }
-    };
+    }, false);
 
     LOG("************************************* ------>>>> sending.");
     xhr.send(null);
diff --git a/js/src/xpconnect/tests/chrome/test_doublewrappedcompartments.xul b/js/src/xpconnect/tests/chrome/test_doublewrappedcompartments.xul
index 6917344af6c2..3cece3a3981c 100644
--- a/js/src/xpconnect/tests/chrome/test_doublewrappedcompartments.xul
+++ b/js/src/xpconnect/tests/chrome/test_doublewrappedcompartments.xul
@@ -30,12 +30,12 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=533596
         var wrappedWin = $('ifr').contentWindow;
         var unwrapped = wrappedWin.wrappedJSObject;
 
-        var readystatechange = unwrapped.xhr.onreadystatechange;
-        is(utils.getClassName(readystatechange), 'Proxy', 'properly wrapped');
-        is(typeof readystatechange.QueryInterface, 'function', 'double wrapped');
+        var filter = unwrapped.filter;
+        is(utils.getClassName(filter), 'Proxy', 'properly wrapped');
+        is(typeof filter.QueryInterface, 'function', 'double wrapped');
 
-        ok(unwrapped.testme(readystatechange),
-           'content didn\'t get a proxy, but another double wrapped object');
+        ok(unwrapped.testme(filter),
+           "content didn't get a proxy, but another double wrapped object");
         SimpleTest.finish();
       }
 
diff --git a/js/src/xpconnect/tests/mochitest/file_doublewrappedcompartments.html b/js/src/xpconnect/tests/mochitest/file_doublewrappedcompartments.html
index b983bf863266..a3ebd681912a 100644
--- a/js/src/xpconnect/tests/mochitest/file_doublewrappedcompartments.html
+++ b/js/src/xpconnect/tests/mochitest/file_doublewrappedcompartments.html
@@ -1,9 +1,9 @@
 <html>
     <head>
         <script>
-            var xhr = new XMLHttpRequest();
-            var readystatechange = function() {};
-            xhr.onreadystatechange = readystatechange;
+            var fcn = function() {};
+            var iter = document.createNodeIterator(document, NodeFilter.SHOW_ELEMENT, fcn, false);
+            var filter = iter.filter;
 
             function testme(obj) {
                 netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
diff --git a/js/src/xpconnect/tests/mochitest/test_bug502959.html b/js/src/xpconnect/tests/mochitest/test_bug502959.html
index 31e270ddd2fa..29537d3d0ab7 100644
--- a/js/src/xpconnect/tests/mochitest/test_bug502959.html
+++ b/js/src/xpconnect/tests/mochitest/test_bug502959.html
@@ -18,10 +18,14 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=502959
 <script type="application/javascript">
 
 /** Test for Bug 502959 **/
-var xhr = new XMLHttpRequest();
+// Whatever you do don't use the word "wrapped" in this function.
+function foo() {
+  ok(true, "Able to call the function");
+}
+
+var iter = document.createNodeIterator(document, NodeFilter.SHOW_ELEMENT, foo, false);
+var doublewrapped = iter.filter;
 
-xhr.onreadystatechange = function() { ok(true, "Able to call the double-wrapped function"); };
-var doublewrapped = xhr.onreadystatechange;
 ok(doublewrapped.toString().indexOf("wrapped") > 0, "got a double-wrapped object back");
 
 (function () {
@@ -29,7 +33,7 @@ ok(doublewrapped.toString().indexOf("wrapped") > 0, "got a double-wrapped object
     Components.utils.forceGC();
 })();
 
-doublewrapped.handleEvent({});
+doublewrapped.acceptNode(document);
 
 </script>
 </pre>
diff --git a/js/src/xpconnect/tests/mochitest/test_bug505915.html b/js/src/xpconnect/tests/mochitest/test_bug505915.html
index 158a95f3d7b1..3f4c7f87eb92 100644
--- a/js/src/xpconnect/tests/mochitest/test_bug505915.html
+++ b/js/src/xpconnect/tests/mochitest/test_bug505915.html
@@ -38,16 +38,6 @@ function go() {
            "threw a security exception instead of an invalid child exception");
     }
 
-    var xhr = new XMLHttpRequest();
-
-    try {
-        xhr.onreadystatechange = ifr.contentWindow;
-        ok(false, "weird behavior");
-    } catch (e) {
-        ok(/NS_ERROR_XPC_SECURITY_MANAGER_VETO/.test(e),
-           "threw a security exception instead of an invalid child exception");
-    }
-
     // Location is always wrapped, so test it separately.
 
     ifr.onload = null;
diff --git a/mobile/modules/LocaleRepository.jsm b/mobile/modules/LocaleRepository.jsm
index c3ba1316d4ba..e7d63a1a4919 100644
--- a/mobile/modules/LocaleRepository.jsm
+++ b/mobile/modules/LocaleRepository.jsm
@@ -105,7 +105,7 @@ var LocaleRepository = {
     request.overrideMimeType("text/xml");
   
     let self = this;
-    request.onreadystatechange = function () {
+    request.addEventListener("readystatechange", function () {
       if (request.readyState == 4) {
         if (request.status == 200) {
           self.log("---- got response")
@@ -122,7 +122,7 @@ var LocaleRepository = {
           Cu.reportError("Locale Repository: Error getting locale from AMO [" + request.status + "]");
         }
       }
-    };
+    }, false);
   
     request.send(null);
   },
diff --git a/netwerk/test/unit/test_xmlhttprequest.js b/netwerk/test/unit/test_xmlhttprequest.js
index 273316ad590c..9a59b88b93d2 100644
--- a/netwerk/test/unit/test_xmlhttprequest.js
+++ b/netwerk/test/unit/test_xmlhttprequest.js
@@ -38,10 +38,10 @@ function run_test()
 
   // Test async XHR sending
   let async = createXHR(true);
-  async.onreadystatechange = function(event) {
+  async.addEventListener("readystatechange", function(event) {
     if (checkResults(async))
       httpserver.stop(do_test_finished);
-  };
+  }, false);
   async.send(null);
   do_test_pending();
 }
diff --git a/toolkit/components/telemetry/TelemetryPing.js b/toolkit/components/telemetry/TelemetryPing.js
index 01db8b20d303..5b047de7695e 100644
--- a/toolkit/components/telemetry/TelemetryPing.js
+++ b/toolkit/components/telemetry/TelemetryPing.js
@@ -320,8 +320,8 @@ TelemetryPing.prototype = {
       if (isTestPing)
         Services.obs.notifyObservers(null, "telemetry-test-xhr-complete", null);
     }
-    request.onerror = function(aEvent) finishRequest(request.channel);
-    request.onload = function(aEvent) finishRequest(request.channel);
+    request.addEventListener("error", function(aEvent) finishRequest(request.channel), false);
+    request.addEventListener("load", function(aEvent) finishRequest(request.channel), false);
 
     request.send(JSON.stringify(payload));
   },
diff --git a/toolkit/components/url-classifier/content/xml-fetcher.js b/toolkit/components/url-classifier/content/xml-fetcher.js
index 6e52e5a0cbe2..1edad3470aff 100644
--- a/toolkit/components/url-classifier/content/xml-fetcher.js
+++ b/toolkit/components/url-classifier/content/xml-fetcher.js
@@ -103,15 +103,14 @@ PROT_XMLFetcher.prototype = {
 
     // Create a closure
     var self = this;
-    this._request.onreadystatechange = function() {
+    this._request.addEventListener("readystatechange", function() {
       self.readyStateChange(self);
-    }
+    }, false);
 
     this._request.send(null);
   },
 
   cancel: function() {
-    this._request.onreadystatechange = null;
     this._request.abort();
     this._request = null;
   },
diff --git a/toolkit/crashreporter/CrashSubmit.jsm b/toolkit/crashreporter/CrashSubmit.jsm
index d1a52d789e4d..6d60e5398619 100644
--- a/toolkit/crashreporter/CrashSubmit.jsm
+++ b/toolkit/crashreporter/CrashSubmit.jsm
@@ -257,7 +257,7 @@ Submitter.prototype = {
     // add the minidump
     formData.append("upload_file_minidump", File(this.dump.path));
     let self = this;
-    xhr.onreadystatechange = function (aEvt) {
+    xhr.addEventListener("readystatechange", function (aEvt) {
       if (xhr.readyState == 4) {
         if (xhr.status != 200) {
           self.notifyStatus(FAILED);
@@ -267,7 +267,7 @@ Submitter.prototype = {
           self.submitSuccess(ret);
         }
       }
-    };
+    }, false);
 
     xhr.send(formData);
     return true;
diff --git a/toolkit/mozapps/extensions/AddonRepository.jsm b/toolkit/mozapps/extensions/AddonRepository.jsm
index 7ebea12f42d6..36a7cf92f95b 100644
--- a/toolkit/mozapps/extensions/AddonRepository.jsm
+++ b/toolkit/mozapps/extensions/AddonRepository.jsm
@@ -1176,8 +1176,10 @@ var AddonRepository = {
     this._request.overrideMimeType("text/xml");
 
     let self = this;
-    this._request.onerror = function(aEvent) { self._reportFailure(); };
-    this._request.onload = function(aEvent) {
+    this._request.addEventListener("error", function(aEvent) {
+      self._reportFailure();
+    }, false);
+    this._request.addEventListener("load", function(aEvent) {
       let request = aEvent.target;
       let responseXML = request.responseXML;
 
@@ -1196,7 +1198,7 @@ var AddonRepository = {
         totalResults = parsedTotalResults;
 
       aHandleResults(elements, totalResults);
-    };
+    }, false);
     this._request.send(null);
   },
 
diff --git a/toolkit/mozapps/extensions/AddonUpdateChecker.jsm b/toolkit/mozapps/extensions/AddonUpdateChecker.jsm
index 7aa1bb2539fe..163b279dc8f8 100644
--- a/toolkit/mozapps/extensions/AddonUpdateChecker.jsm
+++ b/toolkit/mozapps/extensions/AddonUpdateChecker.jsm
@@ -451,8 +451,8 @@ function UpdateParser(aId, aType, aUpdateKey, aUrl, aObserver) {
     this.request.channel.loadFlags |= Ci.nsIRequest.LOAD_BYPASS_CACHE;
     this.request.overrideMimeType("text/xml");
     var self = this;
-    this.request.onload = function(event) { self.onLoad() };
-    this.request.onerror = function(event) { self.onError() };
+    this.request.addEventListener("load", function(event) { self.onLoad() }, false);
+    this.request.addEventListener("error", function(event) { self.onError() }, false);
     this.request.send(null);
   }
   catch (e) {
diff --git a/toolkit/mozapps/extensions/LightweightThemeManager.jsm b/toolkit/mozapps/extensions/LightweightThemeManager.jsm
index e9d0a2cfccee..63ac4db23635 100644
--- a/toolkit/mozapps/extensions/LightweightThemeManager.jsm
+++ b/toolkit/mozapps/extensions/LightweightThemeManager.jsm
@@ -227,7 +227,7 @@ var LightweightThemeManager = {
     req.open("GET", theme.updateURL, true);
 
     var self = this;
-    req.onload = function () {
+    req.addEventListener("load", function () {
       if (req.status != 200)
         return;
 
@@ -240,7 +240,7 @@ var LightweightThemeManager = {
       var currentTheme = self.currentTheme;
       if (currentTheme && currentTheme.id == theme.id)
         self.currentTheme = newData;
-    };
+    }, false);
 
     req.send(null);
   },
diff --git a/toolkit/mozapps/extensions/nsBlocklistService.js b/toolkit/mozapps/extensions/nsBlocklistService.js
index 7efc0ee8ad1a..23cd11a75a54 100644
--- a/toolkit/mozapps/extensions/nsBlocklistService.js
+++ b/toolkit/mozapps/extensions/nsBlocklistService.js
@@ -546,8 +546,8 @@ Blocklist.prototype = {
     request.QueryInterface(Components.interfaces.nsIJSXMLHttpRequest);
 
     var self = this;
-    request.onerror = function(event) { self.onXMLError(event); };
-    request.onload  = function(event) { self.onXMLLoad(event);  };
+    request.addEventListener("error", function(event) { self.onXMLError(event); }, false);
+    request.addEventListener("load", function(event) { self.onXMLLoad(event);  }, false);
     request.send(null);
 
     // When the blocklist loads we need to compare it to the current copy so
diff --git a/toolkit/mozapps/update/nsUpdateService.js b/toolkit/mozapps/update/nsUpdateService.js
index b856c81f33b4..8f365e56df12 100644
--- a/toolkit/mozapps/update/nsUpdateService.js
+++ b/toolkit/mozapps/update/nsUpdateService.js
@@ -2155,9 +2155,9 @@ Checker.prototype = {
     this._request.setRequestHeader("Cache-Control", "no-cache");
 
     var self = this;
-    this._request.onerror     = function(event) { self.onError(event);    };
-    this._request.onload      = function(event) { self.onLoad(event);     };
-    this._request.onprogress  = function(event) { self.onProgress(event); };
+    this._request.addEventListener("error", function(event) { self.onError(event); } ,false);
+    this._request.addEventListener("load", function(event) { self.onLoad(event); }, false);
+    this._request.addEventListener("progress", function(event) { self.onProgress(event); }, false);
 
     LOG("Checker:checkForUpdates - sending request to: " + url);
     this._request.send(null);
diff --git a/toolkit/mozapps/update/test/unit/head_update.js.in b/toolkit/mozapps/update/test/unit/head_update.js.in
index e1d475e0a824..b7195d7f90bf 100644
--- a/toolkit/mozapps/update/test/unit/head_update.js.in
+++ b/toolkit/mozapps/update/test/unit/head_update.js.in
@@ -1007,6 +1007,9 @@ xhr.prototype = {
   _onload: null,
   set onload(val) { gXHR._onload = makeHandler(val); },
   get onload() { return gXHR._onload; },
+  addEventListener: function(event, val, capturing) {
+    eval("gXHR._on" + event + " = val");
+  },
   flags: AUS_Ci.nsIClassInfo.SINGLETON,
   implementationLanguage: AUS_Ci.nsIProgrammingLanguage.JAVASCRIPT,
   getHelperForLanguage: function(language) null,
diff --git a/toolkit/mozapps/update/test/unit/test_0020_general.js b/toolkit/mozapps/update/test/unit/test_0020_general.js
index 4b8c4be4b591..c24a7e6f8dac 100644
--- a/toolkit/mozapps/update/test/unit/test_0020_general.js
+++ b/toolkit/mozapps/update/test/unit/test_0020_general.js
@@ -87,7 +87,7 @@ function callHandleEvent() {
     gXHR.responseXML = null;
   }
   var e = { target: gXHR };
-  gXHR.onload.handleEvent(e);
+  gXHR.onload(e);
 }
 
 // update xml not found
diff --git a/toolkit/mozapps/update/test/unit/test_0030_general.js b/toolkit/mozapps/update/test/unit/test_0030_general.js
index 3fcab51e4336..e7f0ced92ee6 100644
--- a/toolkit/mozapps/update/test/unit/test_0030_general.js
+++ b/toolkit/mozapps/update/test/unit/test_0030_general.js
@@ -77,7 +77,7 @@ function callHandleEvent() {
   catch(e) {
   }
   var e = { target: gXHR };
-  gXHR.onload.handleEvent(e);
+  gXHR.onload(e);
 }
 
 // Helper function for testing mar downloads that have the correct size
diff --git a/toolkit/mozapps/update/test/unit/test_0040_general.js b/toolkit/mozapps/update/test/unit/test_0040_general.js
index b6d02efae83b..8c8e5500ea58 100644
--- a/toolkit/mozapps/update/test/unit/test_0040_general.js
+++ b/toolkit/mozapps/update/test/unit/test_0040_general.js
@@ -63,7 +63,7 @@ function end_test() {
 // call the nsIDOMEventListener's handleEvent method for onload.
 function callHandleEvent() {
   var e = { target: gXHR };
-  gXHR.onload.handleEvent(e);
+  gXHR.onload(e);
 }
 
 // Helper function for parsing the result from the contructed url
diff --git a/toolkit/mozapps/update/test/unit/test_0050_general.js b/toolkit/mozapps/update/test/unit/test_0050_general.js
index a707559ca871..6542a4049582 100644
--- a/toolkit/mozapps/update/test/unit/test_0050_general.js
+++ b/toolkit/mozapps/update/test/unit/test_0050_general.js
@@ -68,7 +68,7 @@ function end_test() {
 function callHandleEvent() {
   gXHR.status = gExpectedStatusCode;
   var e = { target: gXHR };
-  gXHR.onload.handleEvent(e);
+  gXHR.onload(e);
 }
 
 // Helper functions for testing nsIUpdateCheckListener statusText
diff --git a/toolkit/mozapps/webapps/OpenWebapps.js b/toolkit/mozapps/webapps/OpenWebapps.js
index 938b2966095d..8a2a06b7ec82 100644
--- a/toolkit/mozapps/webapps/OpenWebapps.js
+++ b/toolkit/mozapps/webapps/OpenWebapps.js
@@ -166,7 +166,7 @@ OpenWebapps.prototype = {
     let xhr = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].createInstance(Ci.nsIXMLHttpRequest);
     xhr.open("GET", aURL, true);
 
-    xhr.onload = function() {
+    xhr.addEventListener("load", function() {
       if (xhr.status == 200) {
         try {
           let manifest = JSON.parse(xhr.responseText);
@@ -185,12 +185,12 @@ OpenWebapps.prototype = {
       else if (aError) {
         aError.handle({ code: "networkError", message: "Unable to retrieve manifest" });
       }      
-    }
+    }, false);
 
-    xhr.onerror = function() {
+    xhr.addEventListener("error", function() {
       if (aError)
         aError.handle({ code: "networkError", message: "Unable to retrieve manifest" });
-    }
+    }, false);
 
     xhr.send(null);
   },