I have already been told how you can do what I need. To open a line as an HTML page without saving it. Instead of an address, you can use the following lines:
data:text/html;base256,<b>hello world</b>
or
data:text/html;base64,PGI+aGVsbG8gd29ybGQ8L2I+4oCL4oCL
It will be executed as HTML. Also, it works in browser (in the address bar)