actionFunction : is way to make AJAX call to server from java script. In this view state could be posted to server ( If immediate = false ) or values could be passed using apex:param ( If immediate = true ) . Visualforce could be rerendered from actionFunction.
Remote Action : is a way to call server methods from java script, also known as JavaScript remoting. Here visualforce could not be rerendered but the response is fetch and used in callback fucntion.
Remote Action : is a way to call server methods from java script, also known as JavaScript remoting. Here visualforce could not be rerendered but the response is fetch and used in callback fucntion.