20160219-js-codecademy

函数(函数名采用驼峰命名)

var divideByThree = function(number) {
    var val = number / 3;
    console.log(val);
};
divideByThree(12);
// 4

Math.random() 返回值介于[0,1)，包括0小于1

编写一个剪刀石头布的游戏

1. 提示框，让用户输入剪刀、石头、布
2. 判断用户输入的内容是否正确，如不符合弹出警告框并再次输入
3. 电脑随机生成剪刀、石头、布
4. 比较用户和电脑的值，判定输赢

var userChoice = prompt("剪刀、石头、布,三选一");
while (userChoice !== "剪刀" && userChoice !== "石头" && userChoice !== "布") {
  confirm("你的输入不正确，请重新选择");
  userChoice = prompt("剪刀、石头、布,三选一");
}
console.log("选手的选择是:" + " " + userChoice);

var computerChoice = Math.random();
if (computerChoice < 0.33) {
    computerChoice = "剪刀";
}
else if (computerChoice <=0.67) {
    computerChoice = "石头";
} else {
    computerChoice = "布";
}
console.log("电脑的选择是:" + " " + computerChoice);

var compare = function(choice1, choice2) {
    if (choice1 === choice2) {
        console.log("打成平手！");
    }
    else if (choice1 === "剪刀") {
        if (choice2 === "石头") {
            console.log("石头获胜");
        }
        else {
            console.log("剪刀获胜");
        }
    }
    else if (choice1 === "石头") {
        if (choice2 === "剪刀") {
            console.log("石头获胜");
        }
        else {
            console.log("布获胜");
        }
    }
    else if (choice1 === "布") {
        if (choice2 === "剪刀") {
            console.log("剪刀获胜");
        }
        else {
            console.log("布获胜");
        }
    }
};
compare(userChoice, computerChoice);