Scratch

You can do this:

when gf clicked
forever
     if <[up arrow v] pressed?>
          change [y] by [15]
     end 
end

block errors are intentional, hope u still understand

by Auto007 to Aditya007 wrote:

You can do this:

when gf clicked
forever
     if <[up arrow v] pressed?>
          change [y] by [15]
     end 
end

block errors are intentional, hope u still understand

About the signature of Aditya007

None of these would work, since they'd simply move the character up, not down.
You want something like this

when gf clicked
forever
if <key [up arrow v] pressed?>
set [jumping v] to [1]
set [yvel v] to [10]
end
change y by (yvel)
change [yvel v] by [-1]
if <touching [ground v]?>
set [yvel v] to [0]
end

This is more psudocode than a working script, but it should show you what you need. Also in your original post, it said about moving in the air, if you have a simple left right moving script, and a "repeat" command for your jump, that will stop you miving while in the air.