form.php
public function submit($additional = false)
    {
        $encoding = $this->encode();
        if ($additional) {
            $encoding->merge($additional);
        }

        return $encoding;
    }
public function submit($additional = false)
    {
        $encoding = $this->encode();
        if ($additional) {
            $encoding->merge($additional);
        }

        return $encoding;
    }
Simply submits the form without the submit button value.
Used when there is only one button or it is unimportant.

@return hash           Submitted values.