Untitled

<html>
<head>
<title>Title of the document</title>
</head>
<?php
    function remove($string)
    {
        $string = str_replace(",", "<br />", $string);
        return $string;
    }

    if($_POST)
    {
        echo remove($_POST['keywords']);
        echo "<br />";
        echo "<br />";
        echo $_POST["keywords"];
    }

?>
<form method="post" action="">
<textarea name="keywords" cols="40" rows="5">
</textarea><br>
<input type="submit" value="Submit" />
</form>