Question

我是JavaScript的新手。我运行我的代码，根据输入计算用户活着的时间。如果您希望看到代码运行，可以在我的班级测试服务器here上找到它。

我的代码的问题是setInterval（）无法正常工作。根据我的理解，我的html页面应该每隔1000毫秒（1秒）更新一次，但是它没有做任何事情，它不会更新。

我之前在一个类似的项目中使用了setInterval（），该项目显示了自Epoch以来的秒数并且工作正常。它更新了应该的秒数。也许我的代码中的其他东西不允许它工作？我通过jslint和jshint运行我的代码，找不到我正在犯的错误。

提前致谢！

function getUserBirthday(myEpoch) {
    "use strict";
    var unixEpoch = new Date() / 1000.0;
    var secondSince = unixEpoch - myEpoch;
    var leftOrAlive = "";
    if (secondSince < 0) {
        leftOrAlive = ": Seconds Left";
        secondSince = secondSince * -1;
    } else {
        leftOrAlive = ": Seconds Alive";
    }
    document.getElementById("secondsAlive").innerHTML = secondSince + leftOrAlive;
    var years = secondSince / 31556926;
    secondSince = secondSince % 31556926;
    var months = secondSince / 2629743;
    secondSince = secondSince % 2629743;
    var days = secondSince / 86400;
    secondSince = secondSince % 86400;
    var hours = secondSince / 3600;
    secondSince = secondSince % 3600;
    var minutes = secondSince / 60;
    secondSince = secondSince % 60;
    var seconds = secondSince;
    //Convert Variables To String
    years = years.toString();
    months = months.toString();
    days = days.toString();
    hours = hours.toString();
    minutes = minutes.toString();
    seconds = seconds.toString();
    //Remove Trailing Decimal Places
    var yearStr = years.slice(0, (years.indexOf(".")));
    var monthStr = months.slice(0, (months.indexOf(".")));
    var dayStr = days.slice(0, (days.indexOf(".")));
    var hourStr = hours.slice(0, (hours.indexOf(".")));
    var minuteStr = minutes.slice(0, (minutes.indexOf(".")));
    var secondStr = seconds.slice(0, (seconds.indexOf(".")));
    //Show Results
    document.getElementById("years").innerHTML = yearStr + ": Years";
    document.getElementById("months").innerHTML = monthStr + ": Months";
    document.getElementById("days").innerHTML = dayStr + ": Days";
    document.getElementById("hours").innerHTML = hourStr + ": Hours";
    document.getElementById("minutes").innerHTML = minuteStr + ": Minutes";
    document.getElementById("seconds").innerHTML = secondStr + ": Second
}

function updateTimeSinceEpoch() {
    "use strict";
    var strDate = prompt("Enter your birthday: ex. November 12, 1996 00:00:00");
    document.getElementById("birthday").innerHTML = strDate;
    var myDate = new Date(strDate); // Your timezone!
    var myEpoch = myDate.getTime() / 1000.0;
    var runFunction = getUserBirthday(myEpoch);
    setInterval(runFunction, 1000);
}

Answer 1

当你使用时：

var runFunction = getUserBirthday(myEpoch);
setInterval(runFunction, 1000);

runFunction变量为undefined，因为getUserBirthday()方法不会返回任何内容。因此，使用此结构，您的函数将只执行一次：

function getUserBirthday(message) {
  console.log(message);
}

var runFunction = getUserBirthday("Hello");
setInterval(runFunction, 1000);

尝试使用以下结构，它应该做的诀窍：

function getUserBirthday(message) {
  console.log(message);
}

setInterval(function() {
  getUserBirthday('Hello');
}, 1000);

setInterval（）无法正常工作

1 个答案: