[Watdaflip]

JavaScript isn't capable of doing this, adding comments takes some sort of script (php, asp, perl, etc) to process the submitted data from a html form, to add it to a database, and to display the contents of the database. No site builder that I know of have a feature like this that you can just drag and drop, there are some that simplify the process, but you will at least need knowledge of the inner logic of how scripts interact with a database.