diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 2ac0ad96bea..81ca3173224 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -73,7 +73,8 @@ nsDocShell::nsDocShell() :
   mTreeOwner(nsnull),
   mChromeEventHandler(nsnull),
   mCurrentScrollbarPref(-1,-1),
-  mDefaultScrollbarPref(-1,-1)
+  mDefaultScrollbarPref(-1,-1),
+  mEODForCurrentDocument (PR_FALSE)
 {
   NS_INIT_REFCNT();
 }
@@ -1893,7 +1894,7 @@ NS_IMETHODIMP nsDocShell::CreateContentViewer(const char* aContentType,
       }
 
    NS_ENSURE_SUCCESS(SetupNewViewer(viewer), NS_ERROR_FAILURE);
-
+   mEODForCurrentDocument = PR_FALSE; // clear the current flag
    return NS_OK;
 }
 
diff --git a/docshell/base/nsDocShell.h b/docshell/base/nsDocShell.h
index 9cdb2f371b4..bb1b278881f 100644
--- a/docshell/base/nsDocShell.h
+++ b/docshell/base/nsDocShell.h
@@ -199,6 +199,11 @@ protected:
    nsPoint                    mDefaultScrollbarPref; // persistent across doc loads
    PRBool                     mUpdateHistoryOnLoad;
    PRBool                     mInitialPageLoad;
+   // this flag is for bug #21358. a docshell may load many urls
+   // which don't result in new documents being created (i.e. a new content viewer)
+   // we want to make sure we don't call a on load event more than once for a given
+   // content viewer. 
+   PRBool                     mEODForCurrentDocument; 
 
    /* WEAK REFERENCES BELOW HERE.
    Note these are intentionally not addrefd.  Doing so will create a cycle.
diff --git a/docshell/base/nsWebShell.cpp b/docshell/base/nsWebShell.cpp
index f3e5a5e23d4..dc6cf696f67 100644
--- a/docshell/base/nsWebShell.cpp
+++ b/docshell/base/nsWebShell.cpp
@@ -2667,7 +2667,7 @@ nsWebShell::OnEndDocumentLoad(nsIDocumentLoader* loader,
   if (loader == mDocLoader) {
     mProcessedEndDocumentLoad = PR_TRUE;
 
-    if (mScriptGlobal) {
+    if (mScriptGlobal && !mEODForCurrentDocument) {
       nsIDocumentViewer* docViewer;
       if (nsnull != mContentViewer &&
           NS_OK == mContentViewer->QueryInterface(kIDocumentViewerIID, (void**)&docViewer)) {
@@ -2685,6 +2685,8 @@ nsWebShell::OnEndDocumentLoad(nsIDocumentLoader* loader,
       }
     }
 
+    mEODForCurrentDocument = PR_TRUE;
+
     // Fire the EndLoadURL of the web shell container
     if (nsnull != aURL) {
        nsAutoString urlString;
diff --git a/webshell/src/nsWebShell.cpp b/webshell/src/nsWebShell.cpp
index f3e5a5e23d4..dc6cf696f67 100644
--- a/webshell/src/nsWebShell.cpp
+++ b/webshell/src/nsWebShell.cpp
@@ -2667,7 +2667,7 @@ nsWebShell::OnEndDocumentLoad(nsIDocumentLoader* loader,
   if (loader == mDocLoader) {
     mProcessedEndDocumentLoad = PR_TRUE;
 
-    if (mScriptGlobal) {
+    if (mScriptGlobal && !mEODForCurrentDocument) {
       nsIDocumentViewer* docViewer;
       if (nsnull != mContentViewer &&
           NS_OK == mContentViewer->QueryInterface(kIDocumentViewerIID, (void**)&docViewer)) {
@@ -2685,6 +2685,8 @@ nsWebShell::OnEndDocumentLoad(nsIDocumentLoader* loader,
       }
     }
 
+    mEODForCurrentDocument = PR_TRUE;
+
     // Fire the EndLoadURL of the web shell container
     if (nsnull != aURL) {
        nsAutoString urlString;