Block/Adminhtml/System/Config/Field/AbstractCallbackUrl.php
protected function _getElementHtml(AbstractElement $element) {
        $callbackUrl= $this->getBaseUrl() . 'checkout_com/' . $this->getControllerUrl();

        $element->setData('value', $callbackUrl);
        $element->setReadonly('readonly');

        return $element->getElementHtml();
    }
protected function _getElementHtml(AbstractElement $element) {
        $callbackUrl= $this->getBaseUrl() . 'checkout_com/' . $this->getControllerUrl();

        $element->setData('value', $callbackUrl);
        $element->setReadonly('readonly');

        return $element->getElementHtml();
    }
protected function _getElementHtml ( AbstractElement $ element ) { $ callbackUrl = $ this -> getBaseUrl ( ) . 'checkout_com/' . $ this -> getControllerUrl ( ) ; $ element -> setData ( 'value' , $ callbackUrl ) ; $ element -> setReadonly ( 'readonly' ) ; return $ element -> getElementHtml ( ) ; }
Overridden method for rendering a field. In this case the field must be only for read.

@param AbstractElement $element
@return string
Overridden method for rendering a field . In this case the field must be only for read .