diff -r -u vanilla.4/typo3/sysext/cms/tslib/class.tslib_fe.php typo3_src-4.0.4/typo3/sysext/cms/tslib/class.tslib_fe.php
--- vanilla.4/typo3/sysext/cms/tslib/class.tslib_fe.php	2006-12-26 21:12:43.000000000 +0100
+++ typo3_src-4.0.4/typo3/sysext/cms/tslib/class.tslib_fe.php	2006-12-26 21:18:09.000000000 +0100
@@ -286,6 +286,7 @@
 		'onmousemove' => array(),
 		'onmouseup' => array(),
 		'onload' => array(),
+		'onunload' => array(),
 	);
 	var $JSCode='';						// Deprecated, use additionalJavaScript instead.
 	var $JSImgCode='';					// Used to accumulate JavaScript loaded images (by menus)
diff -r -u vanilla.4/typo3/sysext/cms/tslib/class.tslib_pagegen.php typo3_src-4.0.4/typo3/sysext/cms/tslib/class.tslib_pagegen.php
--- vanilla.4/typo3/sysext/cms/tslib/class.tslib_pagegen.php	2006-12-26 21:12:43.000000000 +0100
+++ typo3_src-4.0.4/typo3/sysext/cms/tslib/class.tslib_pagegen.php	2006-12-26 21:19:12.000000000 +0100
@@ -337,7 +337,12 @@
 			$setEvents[]='	document.onload=T3_onloadWrapper;';
 			$setBody[]='onload="T3_onloadWrapper();"';
 		}
-
+		if (is_array($GLOBALS['TSFE']->JSeventFuncCalls['onunload']) && count($GLOBALS['TSFE']->JSeventFuncCalls['onunload']))	{
+			$functions[]='	function T3_onunloadWrapper()	{	'.implode('   ',$GLOBALS['TSFE']->JSeventFuncCalls['onunload']).'	}';
+			$setEvents[]='	document.onunload=T3_onloadWrapper;';
+			$setBody[]='onunload="T3_onunloadWrapper();"';
+		}
+		
 		return Array(count($functions)?'
 <script type="text/javascript">
 	/*<![CDATA[*/