Vehicle scripting - checking that wheels are on the ground

I've been experimenting with vehicles and now have a four wheel steering jeep I can drive around. However, I need to limit acceleration to situations where the wheels are on the ground. I had a look at the RaycastCar.cs script from the car playground demo and, while I think I understand the concept, I could really do with a Javascript example. Can anyone help?

In my vehicle script I use four game object references to control my wheels:

var wheelFrontLeft : GameObject;
var wheelFrontRight : GameObject;
var wheelBackLeft : GameObject;
var wheelBackRight : GameObject;

How do I check that these are currently in contact with something else? Any tips are gratefully recieved.

 

I tried that using the RaycastCar.cs script as a guide but got loads of errors. Is 'for (c in info.contacts)' the correct code to use in a Javascript script?
I think I need an actual Javascript example to help me understand this. Is there any chance of getting a Javascript version of RaycastCar.cs? Sorry to be a pain, but without documentation I'm finding it hard going.

 

Much appreciated. I'll let you know how I get on.

 

I'm afraid I just can't get this to work. I even tried changing the car playground demo to use the javascript version of RaycastCar instead of the original one. It threw lots of errors and refused to work.
When I try to use the OnCollisionStay function in my script Unity either complains about extra '}' characters or gives a general 'script error'. I'm probably being thick, but is the RaycastCar.js file completely written in javascript? I ask because the following doesn't look quite like javascript to me:

function OnCollisionStay (Collision collision) {
foreach (ContactPoint c in collision.contacts)
{
Transform thisTransform = c.thisCollider.transform;
if (thisTransform == backLeftWheel || thisTransform == backRightWheel)
hasWheelContact = true;
}
hasGroundContact = true;
}

The variable types seem to be declared as if the language being used is actually C# or similar. E.g. 'Transform thisTransform'. I thought "Ah, I'll just take out the type declarations and make it like javascript." When I tried that I got errors such as 'The message parameter has to be of type: P7Contact.'

I'm probably making really obvious mistakes, but it's very hard without documentation. If you can point me in the right direction I'd appreciate it.

I've attached my vehicle script. Try not to laugh at it

 

Thanks for that. The code looks much clearer now. I'll give a go.