display: none;... Why not just use <! - - notes? - - - > is there a reason or special thing?

Answer 1

You might not want to touch the HTML once created, but set the property from a JavaScript using DOM based on some condition dynamically based on user inputs.

Answer 2

<! - - notes? - - - > is just a comment in html which the browser does not display. display: none; is css code for removing an element that is already displayed on your site.
Example:

<p>This is a paragraph on my website</p>

p {
display: none;
}

^ That removes the paragraph from the webpage and the space that the element contains.

Answer 3

so the programmer can change the code and can make the content appears to user....using comment,he may get confused ;whether it is fr programmer or user