// retrieve possible resolutions
$res_list = `/usr/bin/scanimage --help | grep -m 1 resolution`;
$start=strpos($res_list,"n")+2;
$length = strpos($res_list,"dpi") -$start;
$list = "".substr($res_list,$start,$length)."";
unset($start);
unset($length);
// change "|" separated string $list into array $resolution values.
$resolution = explode("|",$list);
//generate html selectbox and store in string $res_box
$res_box = html_selectbox(resolution,$resolution,$resolution);
//display the select box
echo "$res_box";