In Javascript, how do I detect if an object exists at a position?

Unity Engine
1

I have an object that I can click and drag on the x axis, i want to only be able to drag this object onto the next platform if the position directly under the object is free of any other objects, so In Javascript, how do I detect if an object exists at a position?

2 
function Update () {[INDENT]     var  down = transform.TransformDirection ([URL="http://unity3d.com/support/documentation/ScriptReference/Vector3-forward.html?from=Physics"]-Vector3.down[/URL]);
[/INDENT][INDENT]     if ([URL="http://unity3d.com/support/documentation/ScriptReference/Physics.Raycast.html"]Physics.Raycast[/URL] (transform.position, down, 10)) {[INDENT]         print ("There is something below the object!");
[/INDENT]}
[/INDENT]}
3

thanks, also, how might i communicate to the object if it exists, like using the SendMessage function?

4

You can use the SendMessage function to call a procedure/function on the gameobject.

This post has other options also:

http://forum.unity3d.com/threads/71458-Accesing-a-Monster-s-Health-and-Hurting-It?highlight=sendmessage