JavaScript to change Year displayed based on month/day

Question

I'm trying to create a script that if today's date is before January 16, the current year will print, but if today's date is greater than or equal to January 16, the following year will print.

I am pretty new to coding JavaScript so perhaps I am just missing something stupid. Can anyone help by looking over this code and tell me what I did wrong?

<script type="text/javascript">
var today = new Date();
var mm = today.getMonth()+1; //January is 0! 
var dd = today.getday();
if (mm < 10) {
    mm = '0'+mm
} 

var today = new Date("mm/dd") 
var other = new Date("01/16")

if (today < other){
var printDate = theDate.getFullYear();  
}

else if (today >= other){
var printDate = theDate.getFullYear()+1;      
}
</script>

Then in the HTML:

<strong>16 January</strong> <script>document.write(printDate);</script>

Output right now is "undefined." Any ideas would be greatly appreciated!

@RedaMeskali Thank you. How can I correct the date comparison? (sorry newbie to Javascript) — beingbecoming, Jun 04 '18 at 23:48
Native Javascript give you very little options for comparing dates. Theoretically you could write your own library to handle this, but there's already a great one called moment.js; https://momentjs.com/ — Ryan Gibbs, Jun 04 '18 at 23:50
refer to [this](https://stackoverflow.com/a/38196054/6158118) answer please. — Reda Meskali, Jun 04 '18 at 23:50
@RedaMeskali I changed my code above. It's still not working but I'm working on it. — beingbecoming, Jun 05 '18 at 00:16
please change today to be a Date object also today = mm/dd means division not concatenation. — Reda Meskali, Jun 05 '18 at 00:16

Dan · Answer 1 · 2018-06-05T00:55:21.057

var today = new Date("mm/dd") // Invalid Date
var other = new Date("01/16") // Tue Jan 16 2001 00:00:00 GMT-0800 (PST)

this should start you on the right process - you need to compare each calendar item (first month, then day) to determine what you are looking for

all the variables you need:

var Today_day = (integer)
var Today_month = (integer)
var Compare_day = (integer) 16 // or 15? not sure about base 0 for a day
var Compare_month = (integer) 0

you know how to get Today_day and Today_month - so you should have everything you need

score 1 · Answer 2 · answered Jun 05 '18 at 01:56

1

The simplified condition is: if month is not January (not 0), or date is after the 15th, then get next year:

var today = new Date, year = today.getFullYear();  

if (today.getMonth() || today.getDate() > 15) year++;

console.log( year );

Or a bit shorter on one line:

var date = new Date, year = date.getFullYear() + (date.getMonth() || date.getDate() > 15)

console.log( year );

answered Jun 05 '18 at 01:56

Slai

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Thanks fro this @Slai. So all that code I worked on can be replaced with this simple condition? – beingbecoming Jun 05 '18 at 02:11
@beingbecoming yes, pretty much without the console.log – Slai Jun 05 '18 at 02:17
Thank you. This is brilliant coding. I've accepted your answer. Thanks again @Slai – beingbecoming Jun 05 '18 at 12:43
I need to get more comfortable with console.log . It seems so useful. – beingbecoming Jun 05 '18 at 12:44

JavaScript to change Year displayed based on month/day

2 Answers2