tic-tac-toe.js Example File

 function winner(board)
 {
     for (var i=0; i<3; ++i) {
         if (board.children[i].state != ""
                 && board.children[i].state == board.children[i+3].state
                 && board.children[i].state == board.children[i+6].state)
             return true

         if (board.children[i*3].state != ""
                 && board.children[i*3].state == board.children[i*3+1].state
                 && board.children[i*3].state == board.children[i*3+2].state)
             return true
     }

     if (board.children[0].state != ""
             && board.children[0].state == board.children[4].state != ""
             && board.children[0].state == board.children[8].state != "")
         return true

     if (board.children[2].state != ""
             && board.children[2].state == board.children[4].state != ""
             && board.children[2].state == board.children[6].state != "")
         return true

     return false
 }

 function restartGame()
 {
     game.running = true

     for (var i=0; i<9; ++i)
         board.children[i].state = ""
 }

 function makeMove(pos, player)
 {
     board.children[pos].state = player
     if (winner(board)) {
         gameFinished(player + " wins")
         return true
     } else {
         return false
     }
 }

 function canPlayAtPos(pos)
 {
     return board.children[pos].state == ""
 }

 function computerTurn()
 {
     var r = Math.random();
     if (r < game.difficulty)
         smartAI();
     else
         randomAI();
 }

 function smartAI()
 {
     function boardCopy(a) {
         var ret = new Object;
         ret.children = new Array(9);
         for (var i = 0; i<9; i++) {
             ret.children[i] = new Object;
             ret.children[i].state = a.children[i].state;
         }
         return ret;
     }

     for (var i=0; i<9; i++) {
         var simpleBoard = boardCopy(board);
         if (canPlayAtPos(i)) {
             simpleBoard.children[i].state = "O";
             if (winner(simpleBoard)) {
                 makeMove(i, "O")
                 return
             }
         }
     }
     for (var i=0; i<9; i++) {
         var simpleBoard = boardCopy(board);
         if (canPlayAtPos(i)) {
             simpleBoard.children[i].state = "X";
             if (winner(simpleBoard)) {
                 makeMove(i, "O")
                 return
             }
         }
     }

     function thwart(a,b,c) {    //If they are at a, try b or c
         if (board.children[a].state == "X") {
             if (canPlayAtPos(b)) {
                 makeMove(b, "O")
                 return true
             } else if (canPlayAtPos(c)) {
                 makeMove(c, "O")
                 return true
             }
         }
         return false;
     }

     if (thwart(4,0,2)) return;
     if (thwart(0,4,3)) return;
     if (thwart(2,4,1)) return;
     if (thwart(6,4,7)) return;
     if (thwart(8,4,5)) return;
     if (thwart(1,4,2)) return;
     if (thwart(3,4,0)) return;
     if (thwart(5,4,8)) return;
     if (thwart(7,4,6)) return;

     for (var i =0; i<9; i++) {
         if (canPlayAtPos(i)) {
             makeMove(i, "O")
             return
         }
     }
     restartGame();
 }

 function randomAI()
 {
     var unfilledPosns = new Array();

     for (var i=0; i<9; ++i) {
         if (canPlayAtPos(i))
             unfilledPosns.push(i);
     }

     if (unfilledPosns.length == 0) {
         restartGame();
     } else {
         var choice = unfilledPosns[Math.floor(Math.random() * unfilledPosns.length)];
         makeMove(choice, "O");
     }
 }

 function gameFinished(message)
 {
     messageDisplay.text = message
     messageDisplay.visible = true
     game.running = false
 }