จะเขียน function html มาใช้งานดูตัวอย่างแล้วไม่เข้าใจ

function td($content,$attr){
        if(!is_array($attr)){
                $attr = array();
        }
        $keys = array_keys($attr);
        $htmlattr = "";
        $n = count($keys);
        for($i=0;$i<$n;$i++){
                if($i != 0){
                        $htmlattr .= " ";
                }
                $htmlattr .= $keys[$i]."=\"".$attr[$keys[$i]]."\n";
        }
        $ret = "<td $htmlattr>$content</td>";

        return $ret;
}

$content = form(
        table(
                textinput_tr("First Name :", "fname").
                textinput_tr("Last Name :", "lname").
                textinput_tr("User name :", "name").
                textinput_tr("Confirm user name :", "cname").
                passinput_tr("Password :", "password").
                passinput_tr("Confirm Password :", "cpassword").
                textinput_tr("Email :", "email").
                textinput_tr("Confirm email :", "cemail")i.
                tr(
                        td(
                                input(
                                        "login"
                                        ,
                                        array("type" => "submit", "value" => "Information Register")
                                )
                        )
                )
                ,
                array("width" => "301", "border" => "0", "cellspacing" => "1", "cellpadding" => "1")
        )
        ,
        array("method" => "post", "action" => "do_create_user.php")
);
$title = "new_user.php";

echo html($title, $content);