$n = 'a';
if (ctype_space($n))
echo "yes<br />";
else
echo "no<br />";
$n = ' ';
if (ctype_space($n))
echo "yes<br />";
else
echo "no<br />";
$n = "\n";
if (ctype_space($n))
echo "yes<br />";
else
echo "no<br />";
$n = "\t";
if (ctype_space($n))
echo "yes<br />";
else
echo "no<br />";
/*
run:
no
yes
yes
yes
*/