How do I get the HTML source from the page?

Question

Is there a way to access the page HTML source code using javascript?

I know that I can use document.body.innerHTML but it contains only the code inside

Answer 1

Provided that

• true html source code is wanted (not current DOM serization)
• and that the page was loaded using GET method,

the page source can be re-downloaded:

fetch(document.location.href)
    .then(response => response.text())
    .then(pageSource => /* ... */)