Explain Browser History and Caching and their difference. Is there a way to modify browser history.

Cache and browser history are not the same thing. Cache means that the browser saves the contents of the page on the client's machine so it can be displayed quickly without going to the server to pull down the content again. Browser history is just an entry in a list somewhere that the browser keeps saying that you visited the page (so that you can easily find something you were looking at the other day but didn't bookmark, or so you can prove that your significant other or children are secretly visiting "naughty" sites) The contents of the page are not saved in browser history, and there's really no way I know of affecting browser history from the server side. There might be some way to do it in JavaScript, though, since it runs on the client side.