(function () {
var outLength = 20, nowValue = 0, prevValue = 1, swapValue;
for (var i = 1, len = outLength - 1; i < len; i++) {
if (i < 3) {
nowValue = 1;
} else {
swapValue = nowValue + prevValue;
prevValue = nowValue;
nowValue = swapValue;
}
console.log(nowValue)
}
}())