CODEWITHSUNDEEP
javascript
422
422

Reputation: 5770

convert date to number of days then do stuff

I want user to enter a date. Using a form, and in the background convert this to number of days. Then desuct a certain number of days, then convert that back to a date.

Example:

Enter the date you were born.

-- convert to xx amount of days (dateindays)

Then make newtotal=dateindays-280

convert newtotal to a date.

Can anyone point me in the right direction of doing this, or do they know some function for doing this?

So lets say :user enters date 13th July 1980 We use js to convert this to total number of days 11,453 days

Then create new function : subtotal=11453-280

And convert those number of days into a date, and echo back on screen.

Upvotes: 1

Views: 13213

Answers (3)

RobG
RobG

Reputation: 147363

Why the conversion to and from days? To add or subtract days, just add or subtract them from the date:

// New date object for 15 November, 2011
var d = new Date(2011, 10, 15);

// Add 5 days
d.setDate(d.getDate() + 5);  // 20-Nov-2011

// Subract 200 days
d.setDate(d.getDate() - 200); // 4-May-2011

Upvotes: 2

Chris
Chris

Reputation: 58142

var d1 = Date.parse("13 July 1980");
d1 = d1 - 24192000000; // 280 days in milliseconds

var newDate = new Date(d1);

console.log(newDate); // will return a date object that represents Oct 07 1979

Then use the following link to format it: http://www.webdevelopersnotes.com/tips/html/10_ways_to_format_time_and_date_using_javascript.php3

Thanks to this SO question for the link: Where can I find documentation on formatting a date in JavaScript?

Upvotes: 3

Sid Malani
Sid Malani

Reputation: 2116

use Date object. Use millis to do the conversion. So if you get the date millis and then subtract or add days * 86400 * 1000 and then create another date object with the result.

var d2 = new Date (d1.getTime() - days_to_subtract * 86400 * 1000);

This might help... http://www.w3schools.com/jsref/jsref_obj_date.asp

Upvotes: 3

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