Generate two-dimensional array and fill it with random boolean value.

var sizeX=3,sizeY=3 ;
 var lock = new Array (sizeX);
  for (var i=0;i<=sizeX;i++) {
    lock[i] = new Array(sizeY);
  }

for (var i =0 ;i <=sizeX ;i++){
     for(var j=0 ;j <=sizeY ;j++){
        lock[i][j]= Math.random () < 0.5 ? true : false;
     }
}