Replacing entire entry-content contents in WordPress

I am developing a WordPress plugin that is inserted onto the page by adding a token to the page content.

So, on the page there is some introductory text with the contents of the plugin below. On postback, I would like to clear the introductory text and just show output from the plugin.

I know I could do this using jQuery by replacing the contents of $(".entry-content").html("plugin output"); but I wanted to ask if there was a WordPress native method of doing this instead.

via Chebli Mohamed