Note that in general, IDE’s like Visual Studio will markup a comment in the context of the current language, by selecting the text you wish to turn into a comment, and then using the Ctrl+K Ctrl+C shortcut, or if you are using Resharper / Intelli-J style shortcuts, then Ctrl+/.
Server side Comments:
Razor .cshtml
@* Comment goes here *@
.aspx
For those looking for the older .aspx
view (and Asp.Net WebForms) server side comment syntax:
<%-- Comment goes here --%>
Client Side Comments
HTML Comment
<!-- Comment goes here -->
Javascript Comment
// One line Comment goes Here /* Multiline comment goes here */
As OP mentions, although not displayed on the browser, client side comments will still be generated for the page / script file on the server and downloaded by the page over HTTP, which unless removed (e.g. minification), will waste I/O, and, since the comment can be viewed by the user by viewing the page source or intercepting the traffic with the browser’s Dev Tools or a tool like Fiddler or Wireshark, can also pose a security risk, hence the preference to use server side comments on server generated code (like MVC views or .aspx pages).