function days_between(date1, date2) {

    // The number of milliseconds in one day
    var ONE_DAY = 1000 * 60 * 60 * 24

    // Convert both dates to milliseconds
    var date1_ms = date1.getTime()
    var date2_ms = date2.getTime()

    // Calculate the difference in milliseconds
    var difference_ms = Math.abs(date1_ms - date2_ms)
    
    // Convert back to days and return
    return Math.round(difference_ms/ONE_DAY)}
	
var current_date = new Date()

// Store the date of the next New Year's Day
var new_years_date = new Date()
new_years_date.setYear(new_years_date.getFullYear() + 1)
new_years_date.setMonth(0)
new_years_date.setDate(1)

// Call the days_between function
var days_left = days_between(current_date, new_years_date)

// Write the result to the page
if (days_left > 1) {
    document.write("<b>-" + (366-days_left) + "+" + days_left + "dias</b>")
}
else {
    document.write("<b>*-" + (366-days_left) + "+" + days_left + "D*</b>")
}