Index: typo3/sysext/install/mod/install.js
===================================================================
--- typo3/sysext/install/mod/install.js	(revision 5027)
+++ typo3/sysext/install/mod/install.js	(working copy)
@@ -43,7 +43,7 @@
 			parameters: '?eID=' + this.eID,
 			onComplete: function(xhr) {
 				document.getElementsByName('TYPO3_INSTALL[localconf.php][encryptionKey]').item(0).value=xhr.responseText;
-			}.bind(this),
+			}.bind(this)
 		});
-	},
-};
\ No newline at end of file
+	}
+};
Index: typo3/sysext/install/mod/class.tx_install.php
===================================================================
--- typo3/sysext/install/mod/class.tx_install.php	(revision 5027)
+++ typo3/sysext/install/mod/class.tx_install.php	(working copy)
@@ -2085,10 +2085,12 @@
 				$out.=$this->wrapInCells('', '<br />');
 
 				if ($this->mode!='123')	{
+					$this->headerStyle .= chr(10) . '
+						<script type="text/javascript" src="' . t3lib_div::getIndpEnv('TYPO3_SITE_URL') . TYPO3_mainDir . 'contrib/prototype/prototype.js"></script>
+						<script type="text/javascript" src="' . t3lib_div::getIndpEnv('TYPO3_SITE_URL') . TYPO3_mainDir . 'sysext/install/mod/install.js"></script>
+					';
 					$out.=$this->wrapInCells('Site name:', '<input type="text" name="TYPO3_INSTALL[localconf.php][sitename]" value="'.htmlspecialchars($GLOBALS['TYPO3_CONF_VARS']['SYS']['sitename']).'">');
 					$out.=$this->wrapInCells('', '<br />');
-					$out.='<script type="text/javascript" src="../sysext/install/mod/install.js"></script>';
-					$out.='<script type="text/javascript" src="../contrib/prototype/prototype.js"></script>';
 					$out.=$this->wrapInCells('Encryption key:', '<a name="set_encryptionKey"></a><input type="text" name="TYPO3_INSTALL[localconf.php][encryptionKey]" value="'.htmlspecialchars($GLOBALS['TYPO3_CONF_VARS']['SYS']['encryptionKey']).'"><br /><input type="button" onclick="EncryptionKey.load(this)" value="Generate random key">');
 					$out.=$this->wrapInCells('', '<br />');
 
Index: typo3/sysext/install/mod/class.tx_install_eid.php
===================================================================
--- typo3/sysext/install/mod/class.tx_install_eid.php	(revision 5027)
+++ typo3/sysext/install/mod/class.tx_install_eid.php	(working copy)
@@ -75,6 +75,7 @@
 	function main()	{
 			// Create output:
 		$this->content = $this->createEncryptionKey();
+		$this->addTempContentHttpHeaders();
 	}
 
 	/**
@@ -83,6 +84,9 @@
 	 * @return	void
 	 */
 	function printContent()	{
+		if (!headers_sent()) {
+			header('Content-Length: ' . strlen($this->content));
+		}
 		echo $this->content;
 	}
 
@@ -93,10 +97,28 @@
 	 * @return string
 	 */
 	function createEncryptionKey($keyLength = 96) {
+		if (!headers_sent()) {
+			header("Content-type: text/plain");
+		}
 		
 		$bytes = t3lib_div::generateRandomBytes($keyLength);
 		return substr(bin2hex($bytes), -96);
 	}
+
+	/**
+	 * Sends cache control headers that prevent caching in user agents.
+	 *
+	 */
+	function addTempContentHttpHeaders() {
+		if (!headers_sent()) {
+				// see RFC 2616
+				// see Microsoft Knowledge Base #234067
+			header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
+			header('Cache-Control: no-cache, must-revalidate');
+			header('Pragma: no-cache');
+			header('Expires: -1');
+		}
+	}
 }
 
 // Make instance: