Index: t3lib/class.t3lib_div.php
===================================================================
--- t3lib/class.t3lib_div.php	(revision 7235)
+++ t3lib/class.t3lib_div.php	(working copy)
@@ -3343,6 +3343,38 @@
 	}
 
 
+	/**
+	 * Function for static version numbers on files, based on the filemtime
+	 * This will make the filename automaticall change when a file is changed, and by that re-cached by the browser
+	 * If the file does not exist physically the original file passed to the function is returned without the timestamp
+	 *
+	 * @param string $file Relative path to file
+	 * @return Relative path with version filename including the timestamp
+	 * @author Lars Houmark <lars@typo3.org>
+	 */
+	public static function createVersionNumberedFile($file) {
+		
+		// start by splitting up the querystring, the part after ? will break filemtime lookup / mainly done for scriptaculous
+		// it will be added back in the end...
+		$lookupFile = explode('?', $file);
+		$name = explode('.', $lookupFile[0]);
+		$extension = array_pop($name);
+		$path = self::resolveBackPath(self::dirname(PATH_thisScript) .'/'. $lookupFile[0]);
+		
+		if (file_exists($path)) {
+			array_push($name, filemtime($path), $extension);
+			$fullName = implode('.', $name);
+			
+			// if there was a querystring in the filename, we need to append it to the current string
+			$fullName .= $lookupFile[1] ? '?'. $lookupFile[1] : '';
+		
+		} else {
+			// file was not found on given location, we will return the path given to this function
+			$fullName = $file;
+		}
+		
+		return $fullName;
+	}
 
 
 
@@ -3352,7 +3384,6 @@
 
 
 
-
 	/*************************
 	 *
 	 * DEBUG helper FUNCTIONS
Index: t3lib/class.t3lib_pagerenderer.php
===================================================================
--- t3lib/class.t3lib_pagerenderer.php	(revision 7235)
+++ t3lib/class.t3lib_pagerenderer.php	(working copy)
@@ -1001,6 +1001,7 @@
 		if (count($this->cssFiles)) {
 			foreach ($this->cssFiles as $file => $properties) {
 				$file = htmlspecialchars(t3lib_div::resolveBackPath($file));
+				$file = (TYPO3_MODE == 'BE' ? t3lib_div::createVersionNumberedFile($file) : $file);
 				$tag = '<link rel="' . $properties['rel'] . '" type="text/css" href="' . $file . '" media="' . $properties['media'] . '"' . ($properties['title'] ? ' title="' . $properties['title'] . '"' : '') . ' />';
 				if ($properties['allWrap'] && strpos($properties['allWrap'], '|') !== FALSE) {
 					$tag = str_replace('|', $tag, $properties['allWrap']);
@@ -1031,6 +1032,7 @@
 				$properties['file'] = htmlspecialchars(
 					t3lib_div::resolveBackPath($properties['file'])
 				);
+				$properties['file'] = (TYPO3_MODE == 'BE' ? t3lib_div::createVersionNumberedFile($properties['file']) : $properties['file']);
 				$tag = '<script src="' . $properties['file'] . '" type="' . $properties['type'] . '"></script>';
 				if ($properties['allWrap'] && strpos($properties['allWrap'], '|') !== FALSE) {
 					$tag = str_replace('|', $tag, $properties['allWrap']);
@@ -1055,6 +1057,7 @@
 		if (count($this->jsFiles)) {
 			foreach ($this->jsFiles as $file => $properties) {
 					$file = htmlspecialchars(t3lib_div::resolveBackPath($file));
+					$file = (TYPO3_MODE == 'BE' ? t3lib_div::createVersionNumberedFile($file) : $file);
 					$tag = '<script src="' . $file . '" type="' . $properties['type'] . '"></script>';
 					if ($properties['allWrap'] && strpos($properties['allWrap'], '|') !== FALSE) {
 						$tag = str_replace('|', $tag, $properties['allWrap']);
@@ -1162,7 +1165,7 @@
 		$out = '';
 
 		if ($this->addPrototype) {
-			$out .= '<script src="' . $this->backPath . 'contrib/prototype/prototype.js" type="text/javascript"></script>' . chr(10);
+			$out .= '<script src="' . t3lib_div::createVersionNumberedFile($this->backPath . 'contrib/prototype/prototype.js') . '" type="text/javascript"></script>' . chr(10);
 			unset($this->jsFiles[$this->backPath . 'contrib/prototype/prototype.js']);
 		}
 
@@ -1181,22 +1184,21 @@
 			if (count($mods)) {
 				$moduleLoadString = '?load=' . implode(',', $mods);
 			}
-
-			$out .= '<script src="' . $this->backPath . 'contrib/scriptaculous/scriptaculous.js' . $moduleLoadString . '" type="text/javascript"></script>' . chr(10);
+			$out .= '<script src="' . t3lib_div::createVersionNumberedFile($this->backPath . 'contrib/scriptaculous/scriptaculous.js' . $moduleLoadString) . '" type="text/javascript"></script>' . chr(10);
 			unset($this->jsFiles[$this->backPath . 'contrib/scriptaculous/scriptaculous.js' . $moduleLoadString]);
 		}
 
 			// include extCore
 		if ($this->addExtCore) {
-			$out .= '<script src="' . $this->backPath . 'contrib/extjs/ext-core' . ($this->enableExtCoreDebug ? '-debug' : '') . '.js" type="text/javascript"></script>' . chr(10);
+			$out .= '<script src="' . t3lib_div::createVersionNumberedFile($this->backPath . 'contrib/extjs/ext-core' . ($this->enableExtCoreDebug ? '-debug' : '') . '.js') . '" type="text/javascript"></script>' . chr(10);
 			unset($this->jsFiles[$this->backPath . 'contrib/extjs/ext-core' . ($this->enableExtCoreDebug ? '-debug' : '') . '.js']);
 		}
 
 			// include extJS
 		if ($this->addExtJS) {
 				// use the base adapter all the time
-			$out .= '<script src="' . $this->backPath . 'contrib/extjs/adapter/' . ($this->enableExtJsDebug ? str_replace('.js', '-debug.js', $this->extJSadapter) : $this->extJSadapter) . '" type="text/javascript"></script>' . chr(10);
-			$out .= '<script src="' . $this->backPath . 'contrib/extjs/ext-all' . ($this->enableExtJsDebug ? '-debug' : '') . '.js" type="text/javascript"></script>' . chr(10);
+			$out .= '<script src="' . t3lib_div::createVersionNumberedFile($this->backPath . 'contrib/extjs/adapter/' . ($this->enableExtJsDebug ? str_replace('.js', '-debug.js', $this->extJSadapter) : $this->extJSadapter)) . '" type="text/javascript"></script>' . chr(10);
+			$out .= '<script src="' . t3lib_div::createVersionNumberedFile($this->backPath . 'contrib/extjs/ext-all' . ($this->enableExtJsDebug ? '-debug' : '') . '.js') . '" type="text/javascript"></script>' . chr(10);
 
 				// add extJS localization
 			$localeMap = $this->csConvObj->isoArray; // load standard ISO mapping and modify for use with ExtJS
@@ -1211,7 +1213,7 @@
 				// TODO autoconvert file from UTF8 to current BE charset if necessary!!!!
 			$extJsLocaleFile = 'contrib/extjs/locale/ext-lang-' . $extJsLang . '.js';
 			if (file_exists(PATH_typo3 . $extJsLocaleFile)) {
-				$out .= '<script src="' . $this->backPath . $extJsLocaleFile . '" type="text/javascript" charset="utf-8"></script>' . chr(10);
+				$out .= '<script src="' . t3lib_div::createVersionNumberedFile($this->backPath . $extJsLocaleFile) . '" type="text/javascript" charset="utf-8"></script>' . chr(10);
 			}
 
 
Index: typo3/alt_main.php
===================================================================
--- typo3/alt_main.php	(revision 7235)
+++ typo3/alt_main.php	(working copy)
@@ -498,8 +498,8 @@
 		$this->generateJScode();
 		$GLOBALS['TBE_TEMPLATE']->JScode= '
 			<script type="text/javascript" src="md5.js"></script>
-			<script type="text/javascript" src="../t3lib/jsfunc.evalfield.js"></script>
-			<script type="text/javascript" src="js/backend.js"></script>
+			<script type="text/javascript" src="' . t3lib_div::createVersionNumberedFile('../t3lib/jsfunc.evalfield.js') . '"></script>
+			<script type="text/javascript" src="' . t3lib_div::createVersionNumberedFile('js/backend.js') . '"></script>
 			';
 		$GLOBALS['TBE_TEMPLATE']->JScode.=$GLOBALS['TBE_TEMPLATE']->wrapScriptTags($this->mainJScode);
 
Index: typo3/backend.php
===================================================================
--- typo3/backend.php	(revision 7235)
+++ typo3/backend.php	(working copy)
@@ -237,7 +237,7 @@
 
 		foreach($this->jsFilesAfterInline as $jsFile) {
 			$GLOBALS['TBE_TEMPLATE']->JScode .= '
-			<script type="text/javascript" src="' . $jsFile . '"></script>';
+			<script type="text/javascript" src="' . t3lib_div::createVersionNumberedFile($jsFile) . '"></script>';
 		}
 
 
Index: typo3/sysext/t3editor/classes/class.tx_t3editor.php
===================================================================
--- typo3/sysext/t3editor/classes/class.tx_t3editor.php	(revision 7235)
+++ typo3/sysext/t3editor/classes/class.tx_t3editor.php	(working copy)
@@ -126,9 +126,9 @@
 
 				// include editor-css
 			$content .= '<link href="' .
-				$GLOBALS['BACK_PATH'] .
+				t3lib_div::createVersionNumberedFile($GLOBALS['BACK_PATH'] .
 				t3lib_extmgm::extRelPath('t3editor') .
-				'res/css/t3editor.css' .
+				'res/css/t3editor.css') .
 				'" type="text/css" rel="stylesheet" />';
 
 				// include editor-js-lib
Index: typo3/sysext/cms/tslib/class.tslib_content.php
===================================================================
--- typo3/sysext/cms/tslib/class.tslib_content.php	(revision 7235)
+++ typo3/sysext/cms/tslib/class.tslib_content.php	(working copy)
@@ -6989,7 +6989,7 @@
 	/*]]>*/
 </script>
 ';
-		$GLOBALS['TSFE']->additionalHeaderData['JSincludeFormupdate']='<script type="text/javascript" src="'.$GLOBALS['TSFE']->absRefPrefix.'t3lib/jsfunc.updateform.js"></script>';
+		$GLOBALS['TSFE']->additionalHeaderData['JSincludeFormupdate']='<script type="text/javascript" src="'. t3lib_div::createVersionNumberedFile($GLOBALS['TSFE']->absRefPrefix.'t3lib/jsfunc.updateform.js') . '"></script>';
 		return $JSPart;
 	}
 
Index: typo3/sysext/cms/layout/db_layout.php
===================================================================
--- typo3/sysext/cms/layout/db_layout.php	(revision 7235)
+++ typo3/sysext/cms/layout/db_layout.php	(working copy)
@@ -426,7 +426,7 @@
 			$this->doc->setModuleTemplate('templates/db_layout.html');
 
 				// JavaScript:
-			$this->doc->JScode = '<script type="text/javascript" src="'.$BACK_PATH.'../t3lib/jsfunc.updateform.js"></script>';
+			$this->doc->JScode = '<script type="text/javascript" src="'. t3lib_div::createVersionNumberedFile($BACK_PATH.'../t3lib/jsfunc.updateform.js') . '"></script>';
 			$this->doc->JScode.= $this->doc->wrapScriptTags('
 				if (top.fsMod) top.fsMod.recentIds["web"] = '.intval($this->id).';
 				if (top.fsMod) top.fsMod.navFrameHighlightedID["web"] = "pages'.intval($this->id).'_"+top.fsMod.currentBank; '.intval($this->id).';
Index: typo3/sysext/recycler/mod1/index.php
===================================================================
--- typo3/sysext/recycler/mod1/index.php	(revision 7235)
+++ typo3/sysext/recycler/mod1/index.php	(working copy)
@@ -158,7 +158,7 @@
 	 */
 	protected function loadStylesheet($fileName) {
 		$fileName = t3lib_div::resolveBackPath($this->doc->backPath . $fileName);
-		$this->doc->JScode.= "\t" . '<link rel="stylesheet" type="text/css" href="' . $fileName . '" />' . "\n";
+		$this->doc->JScode.= "\t" . '<link rel="stylesheet" type="text/css" href="' . t3lib_div::createVersionNumberedFile($fileName) . '" />' . "\n";
 	}
 
 	/**
@@ -169,7 +169,7 @@
 	 */
 	protected function loadJavaScript($fileName) {
 		$fileName = t3lib_div::resolveBackPath($this->doc->backPath . $fileName);
-		$this->doc->JScode.= "\t" . '<script language="javascript" type="text/javascript" src="' . $fileName . '"></script>' . "\n";
+		$this->doc->JScode.= "\t" . '<script language="javascript" type="text/javascript" src="' . t3lib_div::createVersionNumberedFile($fileName) . '"></script>' . "\n";
 	}
 
 	/**