Increase number twice a week

Question

How would you increase a a number on a webpage twice a week on specific days and times?

For example the webpage would read:

"2 Apples"

However every Tuesday & Thursday at 9:00pm the number should increase by two.

So by Friday the number should have increased to 6 "Apples"

What's a simple way to increment this in Javascript, php or Jquery?

Answer 1

As it was mentionned in the comments, I advise you to use a cron to handle this.

First, you have to store your value somewhere (file, databse, ...). Then, you should create a cron job, that runs a code that increase and update your value at the given days of the week.

Some help about crons : https://en.wikipedia.org/wiki/Cron#Examples

I would add this post about cron and php : Executing a PHP script with a CRON Job

Hope it helps

Answer 2

Here a Javascript version, you can pass it the date it should start counting, the date you want to know the ammount of apples of, the days of the week apples will be added, the hours of the day the updat will take place and the ammount of apples that will be added on each of these dates.

Date.prototype.addDays = function (days) {
    var result = new Date(this);
    result.setDate(result.getDate() + days);
    return result;
}
Date.prototype.addHours = function (hours) {
    var result = new Date(this);
    result.setHours(result.getHours() + hours);
    return result;
}

function getApples(startdate, date, updateDays, updateTime, applesPerUpdate) {
    var startDay = startdate.getDay();
    var firstUpdateDate;
    for(day of updateDays) {
        if (day >= startDay) {//assumes startdate has no time added
            firstUpdateDate = startdate.addDays(day - startDay).addHours(updateTime);
            break;
        }
    }
    if (!firstUpdateDate)
        firstUpdateDate = startdate.addDays(7 - (startDay - updateDays[0])).addHours(updateTime);

    var updateDaysReverse = updateDays.slice(0).reverse();//clones the array

    var dateDay = date.getDay();
    var lastUpdateDate;
    for(day of updateDaysReverse) {
        if (day < dateDay || day == dateDay && date.getHours() > updateTime) {
            lastUpdateDate = date.addDays(day - dateDay);
            break;
        }
    }
    if (!lastUpdateDate)
        lastUpdateDate = date.addDays(updateDaysReverse[0] - (7 + dateDay));
    lastUpdateDate = new Date(Date.UTC(1900 + lastUpdateDate.getYear(), lastUpdateDate.getMonth(), lastUpdateDate.getDate(), updateTime, 0, 0, 0));

    var secs = Math.trunc((lastUpdateDate - firstUpdateDate));
    if (secs < 0) return 0;

    var dayDiffs = [];
    for(day of updateDays)
        dayDiffs.push(day - updateDays[0]);

    var weeks = Math.trunc(secs / 604800000);
    var days = Math.trunc((secs % 604800000) / 86400000);
    var apples = weeks * updateDays.length;

    for(diff of dayDiffs)
    {
        if (diff <= days)
            apples++;
        else
            break;
    }
    return apples * applesPerUpdate;
}
// important, day and month is zero-based
var startDate = new Date(Date.UTC(2016, 01, 07, 0, 0, 0, 0));
var updateDays = [2, 4];// 0 = sunday , have to be in order and must be 0 <= x < 7
var updateTime = 9;

console.log(getApples(startDate, new Date(), updateDays, updateTime, 2));

Was more coplicated than I thaught, and i havn't testet it much, so there may be bugs.

Here is a plunker to play with the values.