Javascript 找不到用户输入的下一个生日之前的天数 下面将得到该人生日前的天数，如果生日已经过了，则会给出你生日前几天的时间！ 我仍然在想，是否有可能计算到下一个生日之前的天数，这需要经过12月，并从1月开始继续计算。我似乎做得不对。 //获取生日和月表 var birthdayMonth=document.getElementById（'selMonth'）.value； var birthday=document.getElementById（'selDay'）.value； //解析生日和月份 birthdayMonth=parseInt（birthdayMonth）； 生日=parseInt（生日）； //设置日期对象 今天=新日期（）；//确定今天的日期 生日=新日期（）；//设置生日对象 生日。设定月（生日月）；//将生日月份设置为12月 生日。设定日期（生日）；//把生日定在15号 如果（今天

试试这个

var birthdayMonth = document.getElementById('selMonth').value;
var birthdayDay = document.getElementById('selDay').value;

birthdayMonth = parseInt(birthdayMonth);
birthdayDay = parseInt(birthdayDay);

    today = new Date( );          // set today's date
    birthday = new Date( );      // set up the Birthday object
    birthday.setMonth(birthdayMonth-1);      // set birthday month to December
    birthday.setDate(birthdayDay);         // set birthday date to the 15th

if (today < birthday)
 {  
     diff = Math.abs(birthday.getTime( ) - today.getTime( ));
     diff = Math.floor(diff / (1000 * 60 * 60 * 24));
     alert('There are ' + diff + ' days until ' + (birthdayMonth)+ ' ' + birthdayDay);
  }
else
{
    alert("B'day has passed!");
}

var birthdayMonth=document.getElementById（'selMonth'）.value；
var birthday=document.getElementById（'selDay'）.value；
birthdayMonth=parseInt（birthdayMonth）；
生日=parseInt（生日）；
今天=新日期（）；//确定今天的日期
生日=新日期（）；//设置生日对象
生日。设置月份（生日月份-1）；//将生日月份设置为12月
生日。设定日期（生日）；//把生日定在15号
如果（今天<生日）
{  
diff=Math.abs（生日.getTime（）-today.getTime（））；
差异=数学楼层（差异/（1000*60*60*24））；
警报（“+（生日月）+”''+生日之前有'+diff+'天）；
}
其他的
{
警惕（“B’天已经过去了！”）；
}

---

希望这有帮助

如果他的生日已经过了今年，你可能不会定下年份

让我说今天是10月28日，所有其他的生日日期>28&&month>10都可以。 但在过去的一个月和过去的日子里，它将不起作用。因此，如果今年的生日已经过了，你应该在这一年中加上1，这样它就可以检查下一个生日（即明年）

today=新日期（）；//确定今天的日期
生日=新日期（）；//设置生日对象
生日。设定月（11）；//将生日月份设置为12月
生日。设定日期（22）；//把生日定在15号
if（today.getTime（）>=birth.getTime（））//如果今年的生日已到，则添加当前年份+1
{
生日.setYear（今天.getYear（）+1）；
}
如果（今天.getTime（）<生日.getTime（））
{diff=birth.getTime（）-today.getTime（）；
差异=数学楼层（差异/（1000*60*60*24））；
文档.写入（“+（生日月+1）+”''+生日之前有'+diff+'天）；
}

在这里，我已经完成了我试图完成的任务。。。这将检查距离上次生日有多少天了。这将检查离下一个生日还有多少天。它还将检查用户是否在今天过生日。 谢谢大家帮我得出这个结论。在你的帮助下，我完成了它！我希望这能帮助任何试图做类似事情的人

var output = '';
        var birthdayMonth = document.getElementById('selMonth').value;
        var birthdayDay = document.getElementById('selDay').value;
        
        birthdayMonth = parseInt(birthdayMonth);
        birthdayDay = parseInt(birthdayDay);
        
        //Date Objects
            today = new Date( );          // set today's date
            birthday = new Date( );      // Birthday object setup e.g(birthday.getTime());
        
            birthday.setMonth(birthdayMonth);      // set birthday month (userInput)
            birthday.setDate(birthdayDay);         // set birthday date (userInput)
        
        //Check if todays the users Birthday
        if(birthday.valueOf() == today.valueOf()){
            sweetAlert("Happy birthday!");  
        }
        
        //Until Next Birthday
        if (today > birthday)
        {
        // If the birthday is passed it will calculate how long until it comes next, even if it's next year.
            birthday.setYear(today.getFullYear() + 1); // Set Year = current year + 1
            diff = Math.abs(birthday.getTime( ) - today.getTime( ));
            diff = Math.floor(diff / (1000 * 60 * 60 * 24)); 
            //alert('There are ' + diff + ' days until your birthday'/*Add this for actual date -> birthday*/); alerting how many days
            output += 'There are ' + diff + ' days until birthday'/*Add this for actual date -> birthday <- */;
        }
        
        //Days since last birthday! e.g(may 20 till today(oct 29))
            birthday.setYear(today.getFullYear()); // Set year is normal. (no +1)
            PRdiff = Math.abs(today.getTime( ) - birthday.getTime( ));
            PRdiff = Math.floor(PRdiff / (1000*60*60*24));
            //alert('It was ' + PRdiff + ' days since your last birthday');  Alerting how many days
            output += '<br />It was ' + PRdiff + ' since your last birthday';
            
            //Output it to the page
            document.getElementById('birthdayOutput').innerHTML = output;

var输出=”；
var birthdayMonth=document.getElementById（'selMonth'）.value；
var birthday=document.getElementById（'selDay'）.value；
birthdayMonth=parseInt（birthdayMonth）；
生日=parseInt（生日）；
//日期对象
今天=新日期（）；//确定今天的日期
生日=新日期（）；//生日对象设置，例如（生日.getTime（））；
生日。设定月（生日月）；//设置生日月份（用户输入）
生日。设定日期（生日）；//设置生日日期（用户输入）
//检查今天是否是用户的生日
如果（生日.valueOf（）==今天.valueOf（））{
sweetAlert（“生日快乐！”）；
}
//直到下一个生日
如果（今天>生日）
{
//如果过了生日，它会计算下一个生日还有多久，即使是明年。
生日.setYear（今天.getFullYear（）+1）；//设置年份=当前年份+1
diff=Math.abs（生日.getTime（）-today.getTime（））；
差异=数学楼层（差异/（1000*60*60*24））；
//提醒（'离您的生日还有'+diff+'天'/*将此添加为实际日期->生日*/）；提醒您还有多少天
输出+='离生日还有'+diff+'天'/*将此添加到实际日期->生日如果您需要计算到B'天的日期，而不考虑年份，这里是答案

var birthdayMonth = document.getElementById('selMonth').value;
var birthdayDay = document.getElementById('selDay').value;

birthdayMonth = parseInt(birthdayMonth);
birthdayDay = parseInt(birthdayDay);

    today = new Date( );          // set today's date
    birthday = new Date( );      // set up the Birthday objectbirthday.setDate(birthdayDay);

    birthday.setMonth(birthdayMonth-1);      // set birthday month to December
    birthday.setDate(birthdayDay);         // set birthday date to the 15th

if (today > birthday)
{
    // If the B'day is less than current day means you are refering to the next B'day
    birthday.setYear(today.getFullYear() + 1); // Set Year = current year + 1
}

diff = Math.abs(birthday.getTime( ) - today.getTime( ));
diff = Math.floor(diff / (1000 * 60 * 60 * 24));
alert('There are ' + diff + ' days until ' + birthday);

您的问题是什么？在尝试使用
birthdayMonth
和
birthdayDay
之前，您已经尝试过记录它们的值了吗？@winterblood我有一个表单，用户可以在其中选择出生日期！我已经尝试过多次获取.value（表示特定日期的数字）（例如：2月）请记住，在Javascript中，月份是0索引的（在setDate中，december是11），如果您的HTML中有值为2的二月，则在使用它之前，您必须先减少birthdayMonth。还请记住，您没有在代码中设置年份-如果生日小于或等于今天的日期，它将尝试计算输入的2014年日期，因此不会将其输入
var output = '';
        var birthdayMonth = document.getElementById('selMonth').value;
        var birthdayDay = document.getElementById('selDay').value;
        
        birthdayMonth = parseInt(birthdayMonth);
        birthdayDay = parseInt(birthdayDay);
        
        //Date Objects
            today = new Date( );          // set today's date
            birthday = new Date( );      // Birthday object setup e.g(birthday.getTime());
        
            birthday.setMonth(birthdayMonth);      // set birthday month (userInput)
            birthday.setDate(birthdayDay);         // set birthday date (userInput)
        
        //Check if todays the users Birthday
        if(birthday.valueOf() == today.valueOf()){
            sweetAlert("Happy birthday!");  
        }
        
        //Until Next Birthday
        if (today > birthday)
        {
        // If the birthday is passed it will calculate how long until it comes next, even if it's next year.
            birthday.setYear(today.getFullYear() + 1); // Set Year = current year + 1
            diff = Math.abs(birthday.getTime( ) - today.getTime( ));
            diff = Math.floor(diff / (1000 * 60 * 60 * 24)); 
            //alert('There are ' + diff + ' days until your birthday'/*Add this for actual date -> birthday*/); alerting how many days
            output += 'There are ' + diff + ' days until birthday'/*Add this for actual date -> birthday <- */;
        }
        
        //Days since last birthday! e.g(may 20 till today(oct 29))
            birthday.setYear(today.getFullYear()); // Set year is normal. (no +1)
            PRdiff = Math.abs(today.getTime( ) - birthday.getTime( ));
            PRdiff = Math.floor(PRdiff / (1000*60*60*24));
            //alert('It was ' + PRdiff + ' days since your last birthday');  Alerting how many days
            output += '<br />It was ' + PRdiff + ' since your last birthday';
            
            //Output it to the page
            document.getElementById('birthdayOutput').innerHTML = output;

var birthdayMonth = document.getElementById('selMonth').value;
var birthdayDay = document.getElementById('selDay').value;

birthdayMonth = parseInt(birthdayMonth);
birthdayDay = parseInt(birthdayDay);

    today = new Date( );          // set today's date
    birthday = new Date( );      // set up the Birthday objectbirthday.setDate(birthdayDay);

    birthday.setMonth(birthdayMonth-1);      // set birthday month to December
    birthday.setDate(birthdayDay);         // set birthday date to the 15th

if (today > birthday)
{
    // If the B'day is less than current day means you are refering to the next B'day
    birthday.setYear(today.getFullYear() + 1); // Set Year = current year + 1
}

diff = Math.abs(birthday.getTime( ) - today.getTime( ));
diff = Math.floor(diff / (1000 * 60 * 60 * 24));
alert('There are ' + diff + ' days until ' + birthday);