diff --git a/webshell/tests/viewer/nsViewerApp.cpp b/webshell/tests/viewer/nsViewerApp.cpp
index 903e9b8bdff..a0716b70f14 100644
--- a/webshell/tests/viewer/nsViewerApp.cpp
+++ b/webshell/tests/viewer/nsViewerApp.cpp
@@ -416,7 +416,8 @@ PrintHelpInfo(char **argv)
   fprintf(stderr, "-A domain -- add a domain/host that should be avoided (e.g. microsoft.com)\n");
   fprintf(stderr, "-N pages -- set the max # of pages to crawl\n");
   fprintf(stderr, "-x -- startup and just shutdown to test for leaks under Purify\n");
-  fprintf(stderr, "-Prt -- printer test will be run\n");
+  fprintf(stderr, "-Prt -- number of the printer test 1=regression, no printout \n");
+  fprintf(stderr, "-B -- Setting for regression output 1=brief, 2=verbose \n");
 #if defined(NS_DEBUG) && defined(XP_WIN)
   fprintf(stderr, "-md # -- set the crt debug flags to #\n");
 #endif
@@ -633,6 +634,15 @@ nsViewerApp::ProcessArguments(int argc, char** argv)
       else if (PL_strcmp(argv[i], "-?") == 0) {
         PrintHelpInfo(argv);
       }
+      else if (PL_strcmp(argv[i], "-B") == 0) {
+        int regressionOutput;
+        i++;
+        if (i>=argc || 1!=sscanf(argv[i], "%d", &regressionOutput)){
+          PrintHelpInfo(argv);
+          exit(-1);
+        }
+        mCrawler->RegressionOutput(regressionOutput);
+      }
       else if (PL_strcmp(argv[i], "-Prt") == 0) {
         int printTestType;
         i++;
diff --git a/webshell/tests/viewer/nsWebCrawler.cpp b/webshell/tests/viewer/nsWebCrawler.cpp
index e6e03066601..546f6a9a021 100644
--- a/webshell/tests/viewer/nsWebCrawler.cpp
+++ b/webshell/tests/viewer/nsWebCrawler.cpp
@@ -204,6 +204,7 @@ nsWebCrawler::nsWebCrawler(nsViewerApp* aViewer)
   LL_I2L(mStartLoad, 0);
   mRegressing = PR_FALSE;
   mPrinterTestType = 0;
+  mRegressionOutputLevel = 0;     // full output
   mIncludeStyleInfo = PR_TRUE;
   mLastWebShell = nsnull;
 }
@@ -992,7 +993,7 @@ nsWebCrawler::PerformRegressionTest(const nsString& aOutputName)
     NS_RELEASE(fu);
     return;
   }
-  rv = fu->CompareRegressionData(f1, f2);
+  rv = fu->CompareRegressionData(f1, f2,mRegressionOutputLevel);
   NS_RELEASE(fu);
 
   char dirName[BUF_SIZE];
diff --git a/webshell/tests/viewer/nsWebCrawler.h b/webshell/tests/viewer/nsWebCrawler.h
index 3b202f211fe..ca7c6333b79 100644
--- a/webshell/tests/viewer/nsWebCrawler.h
+++ b/webshell/tests/viewer/nsWebCrawler.h
@@ -71,6 +71,8 @@ public:
 
   void SetPrintTest(PRInt32 aTestType) { mPrinterTestType = aTestType; }
 
+  void RegressionOutput(PRInt32 aRegressionOutputLevel) { mRegressionOutputLevel = aRegressionOutputLevel; }
+
   void EnableJiggleLayout() {
     mJiggleLayout = PR_TRUE;
   }
@@ -179,6 +181,7 @@ protected:
   PRBool mVerbose;
   PRBool mRegressing;
   PRInt32 mPrinterTestType;
+  PRInt32 mRegressionOutputLevel;
   nsString mRegressionDir;
   PRBool mIncludeStyleInfo;