How do I replace windows.open pop-up with a model?

Question

Using php curl as a submit in form, the received url is implemented as "windows.open pop-up". But I can't hide the title bar so I'm going to replace it with Modal. How do I express the redirected url on a modal body? Or which search keyword should I use?

my windows.open pop-up source code

if ($status_code == 200) {
$output_arr = json_decode($output, true);    
$page = $output_arr['next_redirect_pc_url'];
echo "
<script>window.open('$page' , 'payviewer', 'width=450,height=500' );</script>
";
}