html codes and css codes can now be written in the content adding section on my site
However, a css code can change the page layout or change things with the size and width settings, and I said, let's write the codes that the user wrote in this iframe, and I said, let's get an iframe.
var f = document.createElement(“iframe”);
f.id = “s”;
f.contentDocument.body.innerHTML = "html code;
it gives an error here too
Uncaught TypeError: Cannot read property 'body' of undefined
so how can i do that