Calculating the number of days since an event took place using Javascript

If you're looking for a way to determine how many days have passed since a given event took place using Javascript, here is a function that will provide you with the basic functionality that you're looking for:

function calculateDaysSinceEvent(eventDateTime) {
    // Obtain the current date and time
    var todaysDateTime = new Date();
    // Calculate the difference in time between today and when the event took place
    var diff = todaysDateTime - eventDateTime;
    // Convert the difference to a value that represents a day and round the value up

    return Math.round(diff/(1000*60*60*24));
}