收集一些有用的php函数---from cmstop

function js_format($string)
{
return addslashes(str_replace(array("\r", "\n"), array('', ''), $string));
}

function text_format($string)
{
return nl2br(str_replace(' ', ' ', htmlspecialchars($string)));
}

function fileext($filename)
{
return pathinfo($filename, PATHINFO_EXTENSION);
}

function str_cutword($string,$length=80,$charset="utf-8",$etc='...')
{
$start = 0;
if (function_exists ("mb_substr" ))
return mb_substr ( $string, $start, $length, $charset );
$re ['utf-8'] = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";
$re ['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";
$re ['gbk'] = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";
$re ['big5'] = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
preg_match_all ( $re [$charset], $string, $match );
$slice = join ( "", array_slice ( $match [0], $start, $length ) );

return $slice.$etc;
}

function str_cut($string, $length, $dot = '...', $charset = 'utf-8')
{
$strlen = strlen($string);
if($strlen <= $length) return $string;
$specialchars = array('&', '"', ''', '<', '>');
$entities = array('&', '"', "'", '<', '>');
$string = str_replace($specialchars, $entities, $string);
$strcut = '';
if(strtolower($charset) == 'utf-8')
{
$n = $tn = $noc = 0;
while($n < $strlen)
{
$t = ord($string[$n]);
if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
$tn = 1; $n++; $noc++;
} elseif(194 <= $t && $t <= 223) {
$tn = 2; $n += 2; $noc += 2;
} elseif(224 <= $t && $t < 239) {
$tn = 3; $n += 3; $noc += 2;
} elseif(240 <= $t && $t <= 247) {
$tn = 4; $n += 4; $noc += 2;
} elseif(248 <= $t && $t <= 251) {
$tn = 5; $n += 5; $noc += 2;
} elseif($t == 252 || $t == 253) {
$tn = 6; $n += 6; $noc += 2;
} else {
$n++;
}
if($noc >= $length) break;
}
if($noc > $length) $n -= $tn;
$strcut = substr($string, 0, $n);
}
else
{
$dotlen = strlen($dot);
$maxi = $length - $dotlen - 1;
for($i = 0; $i < $maxi; $i++)
{
$strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
}
}
return $strcut.$dot;
}