The remove_special_characters_basic.php page just does some htmlentities work. This page performs some additional work to try and remove the extended smart quotes etc from MS Word. This form will test some input and display the results both as the translated text and as the displayed results. The PHP code is further down the page if anyone is interested!
Firstly, please note that this page has a meta tag of:
// do it again to make it look right on the form
$final = htmlentities("$body",ENT_COMPAT,ISO-8859-15);
// this is when we want to translate it back
$trans_tbl = get_html_translation_table (HTML_ENTITIES);
$trans_tbl = array_flip ($trans_tbl);
$my_text = strtr($my_text, $trans_tbl);