Index: misc/teaser.js
===================================================================
RCS file: /cvs/drupal/drupal/misc/teaser.js,v
retrieving revision 1.12
diff -u -p -r1.12 teaser.js
--- misc/teaser.js	9 Jan 2008 12:10:04 -0000	1.12
+++ misc/teaser.js	18 May 2009 02:31:40 -0000
@@ -71,10 +71,10 @@ Drupal.behaviors.teaser = function(conte
     $(include).parent().parent().before(button);
 
     // Extract the teaser from the body, if set. Otherwise, stay in joined mode.
-    var text = body.val().split('<!--break-->', 2);
-    if (text.length == 2) {
-      teaser[0].value = trim(text[0]);
-      body[0].value = trim(text[1]);
+    var text = body.val().split('<!--break-->');
+    if (text.length >= 2) {
+      teaser[0].value = trim(text.shift());
+      body[0].value = trim(text.join('<!--break-->'));
       $(teaser).attr('disabled', '');
       $('input', button).val(Drupal.t('Join summary')).toggle(join_teaser, split_teaser);
     }