Jump Script ow to make it???

Hello i am learning how to program in JS i have learned the basic and managed to make script for my 2d game so that player can move but i just cant figure out how to make him jump i tried looking at unity third person tutorial but it even confused me more.So i would like to get some help.

here have a look at my previous ans:

http://answers.unity3d.com/questions/53403/making-a-jump-button/53404#53404 hope it helps :)

MC halo pls replay as fast as possible i got the problem it can jump but it cant move left and rightso when i press right arrow or left it jumps or flies. Check this link pls http://forum.unity3d.com/threads/87108-Jump-walk-problem!