You can simply use this bootstrap helper to dialogs (only 5 kB)
it has support for ajax request, iframes, common dialogs, confirm and prompt!
you can use it as:
eModal.iframe('http://someUrl.com', 'This is a tile for iframe', callbackIfNeeded);
eModal.alert('The message', 'This title');
eModal.ajax('/mypage.html', 'This is a ajax', callbackIfNeeded);
eModal.confirm('the question', 'The title', theMandatoryCallback);
eModal.prompt('Form question', 'This is a ajax', theMandatoryCallback);
this provide a loading progress while loading the iframe!
No html required.
You can use a object literal as parameter to extra options.
Check the site form more details.
best,