Solved

<?php
/*Solved !
Thanks to RefnaLdi Hakim*/
if(isset($_POST['btnSmt'])){
$list = @trim($_POST['txValue']);
$exp = explode("\n", $list);
$result = null;
for($i=0; $i<count($exp); $i++){
$preg = preg_replace("#\n|\r|\r\n#", '', $exp[$i]);
$result.= "Start ".$preg." Finish"."\n";}
}else{
$result = null;
$list = null;
}
?>
<html>
<form method=POST action="<?php $_SERVER['PHP_SELF']; ?>">
<textarea cols="50" rows="10" name="txValue"><?php echo $list; ?></textarea><br>
<input type="submit" name="btnSmt">
</form>
<textarea cols="50" rows="10" name="txResult" readonly><?php echo $result; ?></textarea><br>
</html>
<!--
- $preg = str_replace(array("\n","\r","\r\n"), '', $exp[$i]);
- $preg = preg_replace("#\n|\r|\r\n#", '', $exp[$i]);
--!>