As per issue #4479 calendar.js and calendar-uncompressed.js overwrite the standard Javascript setFullYear(year,month,day) function with setFullYear(year).

This means scripts that use javascript's setFullYear function on a page that has the standard datetimepicker loaded may not function correctly as parameters other than year are ignored.

Testing instructions

Before applying this patch make sure the calendar.js is being loaded.

1. Easiest way to do this is to add Jhtml::_('behavior.calendar'); to your active template index.php file.
2. Open your site and then use Chrome developer tools to run the following at the JS console. (thanks @Fedik for picking up my previous mistake)

// define date var:
var date = new Date();
// check the date:
console.log('Original: ' + date.toLocaleDateString());
// try change the date
date.setFullYear(2014,11,25);
// check result
console.log('Changed: ' + date.toLocaleDateString());

The changed will be the same as the Original as only the year will have been updated.

Now test the actual patch.

1. Apply the patch and refresh the page.
2. Using the Javascript console re-run the code from before. This time the changed date should be Christmas day.

Question? Will anything break?

All I have done is remove the offending setFullYear function from the calendar.js and calendar-uncompressed.js. Is this safe? The date pickers in the back end still worked correctly after I made this change, so I don't think it breaks anything obvious.

I checked Jalili calendar addon and they didn't actually define setFullYear themselves. Rather it defined _calSetFullYear so possibly this isn't going to break anything. Can someone with more historical knowledge advise?

Cheers,
Eric.