text omzetten naar url

<a href="www.site.be">www.site.be
</a>

<a href="www.site.be">www.site.be
</a>

<?php
echo ("<a href=\"".$_GET['site']."\">".$_GET['site']."</a>");
?>

<?php
echo ("<a href=\"".$_GET['site']."\">".$_GET['site']."</a>");
?>

$urls = explode(" " , $_POST['urls'] ); //" " is splitsen op spaties
foreach( $urls as $value ) 
{
    echo '<a href="'.$value.'">'.$value.'</a>';
}

$urls = explode(" " , $_POST['urls'] ); //" " is splitsen op spaties
foreach( $urls as $value ) 
{
    echo '<a href="'.$value.'">'.$value.'</a>';
}