A UTF-8 compatible htmlspecialchars() with optional arguments. An example of a function with optional arguments.

hsc.php

<?php
function hsc($value, $args=NULL) {
    $default_args = array('flags'=>ENT_COMPAT, 'encoding'=>'UTF-8', 'double_encode'=>FALSE);
    extract(array_merge($default_args, (array)$args));
    return htmlspecialchars((string)$value, (int)$flags, (string)$encoding, (bool)$double_encode);
}