How do I display highscores on screen?

I'm creating a simple top down shooter for my school and i want to know how i can display the players highscore for that session on screen.

For example, if the player gets 100kills in one play, but only 80 on the next time they play in the same session, how can i display the highest score? I don't want it to save forever, just until they switch off the game, than the highscore resets.

Just like this game. helicoptergame.net

Thankyou!

Use webstorage, and save it as a session key instead of local key

I was thinking that, but i have no idea what what events and actions to do.

Any Capx file?

Do a search of the forums (using the search forums box at the top of the page) and you will find many examples with Capx files. Here, I searched it for you: scirra.com/forum/search