Date of last modification made on a webpage

With PHP it is possible to automatically display the last modification of the current page: 

<? 
setlocal(LC_ALL,'english');  
echo "Last modification made on ".date("l j F Y at H:i", filemtime($SCRIPT_FILENAME)); 
?> 

Alternatively you can use: 

<? 
setlocal(LC_ALL,'english');  
echo " Last modification made on ".date("l j F Y at H:i", getlastmod()); 
?>