How can I use the Setfocus to an input textbox?

stop();
 
 
Line1.buttonMode = true;
Line1.addEventListener(MouseEvent.ROLL_OVER, overHandler1);
Line1.addEventListener(MouseEvent.ROLL_OUT, outHandler1);
function overHandler1(event:MouseEvent) {
	event.target.gotoAndPlay("over");
}
function outHandler1(event:MouseEvent) {
	event.target.gotoAndPlay("out");
}
 
 
Line2.buttonMode = true;
Line2.addEventListener(MouseEvent.ROLL_OVER, overHandler2);
Line2.addEventListener(MouseEvent.ROLL_OUT, outHandler2);
function overHandler2(event:MouseEvent) {
	event.target.gotoAndPlay("over");
}
function outHandler2(event:MouseEvent) {
	event.target.gotoAndPlay("out");
}
 
 
Line3.buttonMode = true;
Line3.addEventListener(MouseEvent.ROLL_OVER, overHandler3);
Line3.addEventListener(MouseEvent.ROLL_OUT, outHandler3);
function overHandler3(event:MouseEvent) {
	event.target.gotoAndPlay("over");
}
function outHandler3(event:MouseEvent) {
	event.target.gotoAndPlay("out");
}
 
 
Line4.buttonMode = true;
Line4.addEventListener(MouseEvent.ROLL_OVER, overHandler4);
Line4.addEventListener(MouseEvent.ROLL_OUT, outHandler4);
function overHandler4(event:MouseEvent) {
	event.target.gotoAndPlay("over");
}
function outHandler4(event:MouseEvent) {
	event.target.gotoAndPlay("out");
}
 
 
Line5.buttonMode = true;
Line5.addEventListener(MouseEvent.ROLL_OVER, overHandler5);
Line5.addEventListener(MouseEvent.ROLL_OUT, outHandler5);
function overHandler5(event:MouseEvent) {
	event.target.gotoAndPlay("over");
}
function outHandler5(event:MouseEvent) {
	event.target.gotoAndPlay("out");
}
 
 
Line6.buttonMode = true;
Line6.addEventListener(MouseEvent.ROLL_OVER, overHandler6);
Line6.addEventListener(MouseEvent.ROLL_OUT, outHandler6);
function overHandler6(event:MouseEvent) {
	event.target.gotoAndPlay("over");
}
function outHandler6(event:MouseEvent) {
	event.target.gotoAndPlay("out");
}
 
 
Line7.buttonMode = true;
Line7.addEventListener(MouseEvent.ROLL_OVER, overHandler7);
Line7.addEventListener(MouseEvent.ROLL_OUT, outHandler7);
function overHandler7(event:MouseEvent) {
	event.target.gotoAndPlay("over");
}
function outHandler7(event:MouseEvent) {
	event.target.gotoAndPlay("out");
}
var resultStr:String = "";
var result:Number = 0;
var counter:Number = 1;
var tboxArr:Array = new Array();	
 
 
calculator();		
function calculator()
{
	tboxArr = new Array(Line1.input1, Line2.input2, Line3.input3, Line4.input4,Line5.input5,Line6.input6, Line7.input7);
	    Line1.input1.tabIndex =1;
		Line2.input2.tabIndex =2;
		Line3.input3.tabIndex =3;
		Line4.input4.tabIndex =4;		
		Line5.input5.tabIndex =5;
		Line6.input6.tabIndex =6;
		Line7.input7.tabIndex =7;		
	for (var i:Number = 0; i<tboxArr.length; i++)
	{ 
		tboxArr[i].border = true;
		tboxArr[i].restrict = "0-9";
		tboxArr[i].type = "input";
		tboxArr[i].addEventListener(Event.CHANGE, clickHandler);
	}
	answer.type = "dynamic";
 
}
function clickHandler(e:Event):void
{			
	result = 0;
	for (var i=0; i<tboxArr.length; i++) 
	{				
		result += Number(TextField(tboxArr[i]).text);
		resultStr = result.toString();
		answer.text = resultStr;
	}
}

                                  

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:
78:
79:
80:
81:
82:
83:
84:
85:
86:
87:
88:
89:
90:
91:
92:
93:
94:
95:
96:
97:
98:
99:
100:
101:
102:
103:
104:
105:
106:
107:
108:
109:
110:
111:
112:
113:
114:
115: