Object Reference not set to an instance o

Questions & Answers
1

Error:

Object reference not set to an
instance of an object GUIFinal.OnGUI
() (at Assets/Standard
Assets/Character/Script/GUIFinal.js:8)

var stringToEdit : String = "Hello World";
var script : Graphics3;
	function OnGUI () {
		// Make a text field that modifies stringToEdit.
		stringToEdit = GUI.TextField (Rect (10, 10, 200, 20), stringToEdit, 25);
		if (GUI.Button(Rect(10,70,50,30),"Click"))
		hand = GameObject.Find("ForUnity/Left Arm").GetComponent(Graphics3);
		hand.url = "https://****BlockedSite/api/get.php?asset=" + stringToEdit;
}
2

You need to wrap two lines after if statement in curly brackets:

if (GUI.Button(Rect(10,70,50,30),"Click"))
{
    hand = GameObject.Find("ForUnity/Left Arm").GetComponent(Graphics3);
    hand.url = "https://****BlockedSite/api/get.php?asset=" + stringToEdit;
}

EDIT: additionally, I see you declared variable named script, but then use variable named hand. I guess this is a typo only, and in your actual code it has the same name.