diffrence b/w render and reload

Reloading is making another http request to the webhost's server. It returns html for your browser to load onto the page.
Rerendering is the act of changing, adding, or removing existing html on the page that has already been served to the browser. No need to interact with the website's server to make these changes. Keep in mind showing the actual content inside the new html element might make a http request.This is the entire point of JavaScript.