Scratch

You need to set your gravity script to detect the platform, and only decrease Y when it isn't being touched.

Either have the platform as a sprite, and use "if touching (sprite)", or have the platform a specific colour and use "if touching colour".

Here is an example of the latter.

http://scratch.mit.edu/projects/Mayhem/15862

It depends on how you have written "gravity" for your sprite.

In effect, though, you need to put a condition on your gravity script so that it only moves your sprite downwards if it isn't touching a platform.

Forever
- If NOT touching (platform)
- change y by -5
wait 0.05

Try something like that, and if you get it workign we can look at teh more advanced idea of it only stopping you falling when you are standing on top of it...

Grab a yellow IF block from the Control instructions

Grab a Not from the green Numbers

Grab a Touching from the blue Sensing controls

Drop the Touching into the Not, drop both into the If then select the name of your platform sprite from the drop down menu on the Touching section.