Barcode::render()
generates an image, not an HTML page with images in it. You'll need to do something like this:
barcode.php:
use Zend\Barcode\Barcode;
$barcodeOptions = array('text' => $_GET['code']);
$rendererOptions = array();
Barcode::render(
'code39', 'image', $barcodeOptions, $rendererOptions
);
And then in your HTML, you reference that script as if it were an image:
<img src="http://domain.com/barcode.php?code=123456" />
<img src="http://domain.com/barcode.php?code=654321" />