Sorry. I don’t understand the issue. Could you write in more detail what you’re trying to achieve?
I use a iframe tag with src is a shapespark link, when render the viewer the iframe will have a content body and include the script contain assetsUrl, I use theIframe2.contentWindow.document.body.innerHTML to get the body content but it was blocked. The purpose I want to have it is so that when the user enters any shapespark link, I will get the assetsUrl.