Suppose  you want to obfuscate an iframe with src=https://www.phpkobo.com/

1) Fetch the content of https://www.phpkobo.com/
	This is the hard part! You will get an error message like this
		---------------------------------------------
		Access to fetch at 'https://www.phpkobo.com/' from origin
		'http://php80ub20.solar.lan' has been blocked by CORS policy:
		No 'Access-Control-Allow-Origin' header is present on the requested resource.
		If an opaque response serves your needs, set the request's mode to 'no-cors'
		to fetch the resource with CORS disabled.
		---------------------------------------------
	* 'Access-Control-Allow-Origin'`を詳しく調べる必要がある。
	* この問題を迂回したければ、JSに代わりに、PHPでFetchする。

2) Add <base href="..."> to the webpage content in order to solve relative paths.

3) Create a blob of the content(https://www.phpkobo.com/)
		var blob = new Blob(['<a id="a"><b id="b">hey!</b></a>'], {type : 'text/html'});

4) Create URL with createObjectURL(blob)
		---------------------------------------------
		var newurl = window.URL.createObjectURL(blob);
		---------------------------------------------

5) Set the URL to an iframe
		---------------------------------------------
		document.getElementById("myFrame").src = newurl;
		---------------------------------------------