accessing and changing a float variable in another script

HI I need to get a float variable that is stored in one script and change the value of that float using another script could you please tell me how to get that value and change it in JavaScript. thank you in advance:)
this is the code I need to access:public var Iron = 500f; the value Iron will be changing over time.

I explain it very clearly here:

and here

The script reference is at http://docs.unity3d.com/412/Documentation/ScriptReference/index.Accessing_Other_Components.html

And simply swapping the names shown in the example there to your scenario gives:

var IronScript : NameOfTheScriptInWhichIronIsDefined;
IronScript = GetComponent("NameOfTheScriptInWhichIronIsDefined");
IronScript.Iron = 500f;