javascript 如何检查日期是否在 30 天内？
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How to check if date is within 30 days?
提问by ssdesign
Possible Duplicate:
Get difference between 2 dates in javascript?
I am storing date variables like this:
我正在存储这样的日期变量：
var startYear = 2011;
var startMonth = 2;
var startDay = 14;
Now I want to check if current day (today) is falling within 30 days of the start date or not. Can I do this?
现在我想检查当前日期（今天）是否在开始日期的 30 天内。我可以这样做吗？
var todayDate = new Date();
var startDate = new Date(startYear, startMonth, startDay+1);
var difference = todayDate - startDate;
????
????
I am not sure if this is syntactically or logically correct.
我不确定这在语法上或逻辑上是否正确。
回答by maerics
In JavaScript, the best way to get the timespan between two dates is to get their "time" value (number of milliseconds since the epoch) and convert that into the desired units. Here is a function to get the number of days between two dates:
在 JavaScript 中，获取两个日期之间的时间跨度的最佳方法是获取它们的“时间”值（自纪元以来的毫秒数）并将其转换为所需的单位。这是一个获取两个日期之间天数的函数：
var numDaysBetween = function(d1, d2) {
var diff = Math.abs(d1.getTime() - d2.getTime());
return diff / (1000 * 60 * 60 * 24);
};
var d1 = new Date(2011, 0, 1); // Jan 1, 2011
var d2 = new Date(2011, 0, 2); // Jan 2, 2011
numDaysBetween(d1, d2); // => 1
var d3 = new Date(2010, 0, 1); // Jan 1, 2010
numDaysBetween(d1, d3); // => 365
回答by Razor Storm
(todayDate.getTime() - startDate.getTime())/(1000*60*60*24.0)
