diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 18f9b05f49b..6eb57c13c3a 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -4453,7 +4453,9 @@ nsGlobalWindow::Print()
         printSettingsService->GetNewPrintSettings(getter_AddRefs(printSettings));
       }
 
+      EnterModalState();
       webBrowserPrint->Print(printSettings, nsnull);
+      LeaveModalState();
 
       PRBool savePrintSettings =
         nsContentUtils::GetBoolPref("print.save_print_settings", PR_FALSE);
@@ -5640,6 +5642,13 @@ nsGlobalWindow::EnterModalState()
     }
   }
   topWin->mModalStateDepth++;
+
+  JSContext *cx = nsContentUtils::GetCurrentJSContext();
+
+  nsIScriptContext *scx;
+  if (cx && (scx = GetScriptContextFromJSContext(cx))) {
+    scx->EnterModalState();
+  }
 }
 
 // static
@@ -5743,6 +5752,13 @@ nsGlobalWindow::LeaveModalState()
       mSuspendedDoc = nsnull;
     }
   }
+
+  JSContext *cx = nsContentUtils::GetCurrentJSContext();
+
+  nsIScriptContext *scx;
+  if (cx && (scx = GetScriptContextFromJSContext(cx))) {
+    scx->LeaveModalState();
+  }
 }
 
 PRBool
diff --git a/dom/base/nsIScriptContext.h b/dom/base/nsIScriptContext.h
index c0a54d91a45..f72ec7aa6da 100644
--- a/dom/base/nsIScriptContext.h
+++ b/dom/base/nsIScriptContext.h
@@ -56,10 +56,10 @@ class nsScriptObjectHolder;
 
 typedef void (*nsScriptTerminationFunc)(nsISupports* aRef);
 
+// 87482b5e-e019-4df5-9bc2-b2a51b1f2d28
 #define NS_ISCRIPTCONTEXT_IID \
-{ /* {09316a0e-8d05-4d26-9efd-8f907a7c79d2} */ \
-  0x09316a0e, 0x8d05, 0x4d26, \
- { 0x9e, 0xfd, 0x8f, 0x90, 0x7a, 0x7c, 0x79, 0xd2 } }
+{ 0x87482b5e, 0xe019, 0x4df5, \
+  { 0x9b, 0xc2, 0xb2, 0xa5, 0x1b, 0x1f, 0x2d, 0x28 } }
 
 /* This MUST match JSVERSION_DEFAULT.  This version stuff if we don't
    know what language we have is a little silly... */
@@ -456,6 +456,9 @@ public:
    */
   virtual nsresult DropScriptObject(void *object) = 0;
   virtual nsresult HoldScriptObject(void *object) = 0;
+
+  virtual void EnterModalState() = 0;
+  virtual void LeaveModalState() = 0;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsIScriptContext, NS_ISCRIPTCONTEXT_IID)
diff --git a/dom/base/nsJSEnvironment.cpp b/dom/base/nsJSEnvironment.cpp
index 017f067227d..8361d9db83b 100644
--- a/dom/base/nsJSEnvironment.cpp
+++ b/dom/base/nsJSEnvironment.cpp
@@ -906,11 +906,13 @@ nsJSContext::DOMOperationCallback(JSContext *cx)
   // ScriptEvaluated to be called, and clearing our operation callback time.
   // See bug 302333.
   PRTime callbackTime = ctx->mOperationCallbackTime;
+  PRTime modalStateTime = ctx->mModalStateTime;
 
   MaybeGC(cx);
 
   // Now restore the callback time and count, in case they got reset.
   ctx->mOperationCallbackTime = callbackTime;
+  ctx->mModalStateTime = modalStateTime;
 
   // Check to see if we are running OOM
   nsCOMPtr<nsIMemory> mem;
@@ -965,15 +967,20 @@ nsJSContext::DOMOperationCallback(JSContext *cx)
 
   PRTime now = PR_Now();
 
-  if (LL_IS_ZERO(callbackTime)) {
+  if (callbackTime == 0) {
     // Initialize mOperationCallbackTime to start timing how long the
     // script has run
     ctx->mOperationCallbackTime = now;
     return JS_TRUE;
   }
 
-  PRTime duration;
-  LL_SUB(duration, now, callbackTime);
+  if (ctx->mModalStateDepth) {
+    // We're waiting on a modal dialog, nothing more to do here.
+
+    return JS_TRUE;
+  }
+
+  PRTime duration = now - callbackTime;
 
   // Check the amount of time this script has been running, or if the
   // dialog is disabled.
@@ -1153,6 +1160,46 @@ nsJSContext::DOMOperationCallback(JSContext *cx)
   return JS_FALSE;
 }
 
+void
+nsJSContext::EnterModalState()
+{
+  if (!mModalStateDepth) {
+    mModalStateTime =  mOperationCallbackTime ? PR_Now() : 0;
+  }
+  ++mModalStateDepth;
+}
+
+void
+nsJSContext::LeaveModalState()
+{
+  if (!mModalStateDepth) {
+    NS_ERROR("Uh, mismatched LeaveModalState() call!");
+
+    return;
+  }
+
+  --mModalStateDepth;
+
+  // If we're still in a modal dialog, or mOperationCallbackTime is still
+  // uninitialized, do nothing.
+  if (mModalStateDepth || !mOperationCallbackTime) {
+    return;
+  }
+
+  // If mOperationCallbackTime was set when we entered the first dialog
+  // (and mModalStateTime is thus non-zero), adjust mOperationCallbackTime
+  // to account for time spent in the dialog.
+  // If mOperationCallbackTime got set while the modal dialog was open,
+  // simply set mOperationCallbackTime to the closing time of the dialog so
+  // that we never adjust mOperationCallbackTime to be in the future. 
+  if (mModalStateTime) {
+    mOperationCallbackTime += PR_Now() - mModalStateTime;
+  }
+  else {
+    mOperationCallbackTime = PR_Now();
+  }
+}
+
 #define JS_OPTIONS_DOT_STR "javascript.options."
 
 static const char js_options_dot_str[]   = JS_OPTIONS_DOT_STR;
@@ -1275,7 +1322,9 @@ nsJSContext::nsJSContext(JSRuntime *aRuntime) : mGCOnDestruction(PR_TRUE)
   mNumEvaluations = 0;
   mTerminations = nsnull;
   mScriptsEnabled = PR_TRUE;
-  mOperationCallbackTime = LL_ZERO;
+  mOperationCallbackTime = 0;
+  mModalStateTime = 0;
+  mModalStateDepth = 0;
   mProcessingScriptTag = PR_FALSE;
 }
 
@@ -3363,7 +3412,8 @@ nsJSContext::ScriptEvaluated(PRBool aTerminated)
   }
 
   if (aTerminated) {
-    mOperationCallbackTime = LL_ZERO;
+    mOperationCallbackTime = 0;
+    mModalStateTime = 0;
   }
 }
 
diff --git a/dom/base/nsJSEnvironment.h b/dom/base/nsJSEnvironment.h
index ca972acd8dd..05a67862d72 100644
--- a/dom/base/nsJSEnvironment.h
+++ b/dom/base/nsJSEnvironment.h
@@ -165,6 +165,9 @@ public:
   virtual nsresult DropScriptObject(void *object);
   virtual nsresult HoldScriptObject(void *object);
 
+  virtual void EnterModalState();
+  virtual void LeaveModalState();
+
   NS_DECL_NSIXPCSCRIPTNOTIFY
 
   static void LoadStart();
@@ -288,6 +291,9 @@ private:
   PRUint32 mDefaultJSOptions;
   PRTime mOperationCallbackTime;
 
+  PRTime mModalStateTime;
+  PRUint32 mModalStateDepth;
+
   // mGlobalWrapperRef is used only to hold a strong reference to the
   // global object wrapper while the nsJSContext is alive. This cuts
   // down on the number of rooting and unrooting calls XPConnect has