frames.php
public function getField($selector)
    {
        for ($i = 0; $i < count($this->frames); $i++) {
            $value = $this->frames[$i]->getField($selector);
            if (isset($value)) {
                return $value;
            }
        }

        return;
    }
public function getField($selector)
    {
        for ($i = 0; $i < count($this->frames); $i++) {
            $value = $this->frames[$i]->getField($selector);
            if (isset($value)) {
                return $value;
            }
        }

        return;
    }
Accessor for a form element value within a page.

@param SimpleSelector $selector    Field finder.

@return string/boolean             A string if the field is present, false if unchecked and
null if missing.