Sliding from stairs

Hi guys, Im currently making FPS and I have dynamic character(just a box for a moment) and I have stairs… I watched few tutorials and made stairs with no collision and invisible plane going along the stairs. The thing is when you standing in the middle of the stairs you always sliding down. What I want is that when I am not moving I want to stay on stairs not to start slide downwards. I checked one youtube video and found game which have something I want to have. Here is the link : Just go to 2:10sec and you will see it. If someone can help find script with that I would be happy, and dont suggest about logic bricks, I tried to do with parents but I failed. Thanks in advance

I believe in under the material settings there is a friction option which, when raised to a high enough level, will stop the sliding problem.

Okay now with friction its not sliding anymore but now my servo control requires much more Linear V and when Im reaching top of the stairs my character just flies far away.:spin: