My code is working properly in Google Chrome, but not in Safari.
I figured out that I need to convert yyyy-MM-dd HH:mm:ss to ISO 8601, but
To make your question easier your problem is with:
new Date('2014-02-18 15:00:48')
This work okay in chrome but not in safari. The mdn talks about ECMAScript 5 ISO-8601 format support says:
Alternatively, the date/time string may be in ISO 8601 format. For example, "2011-10-10" (just date) or "2011-10-10T14:48:00" (date and time) can be passed and parsed.
If you include T it works:
new Date('2014-02-18T15:00:48')
You can use new Date('2014-02-18T15:00:48'.replace(/\s/, 'T')).
If you handle a lot of cases like this I will recommend using moment which seems to handle this case very well with or without T: parsing from string. Additionally your whole example is easier with momentjs:
var minutes = moment().diff("2014-02-18 15:00:48", 'minutes');