JavaScript: friendly timezone abbreviations in the client ("EDT", "CST", "GMT", etc.)
| /* Friendly timezone abbreviations in client-side JavaScript | |
| `tzAbbr()` or `tzAbbr(new Date(79,5,24))` | |
| => "EDT", "CST", "GMT", etc.! | |
| There's no 100% reliable way to get friendly timezone names in all | |
| browsers using JS alone, but this tiny function scours a | |
| stringified date as best it can and returns `null` in the few cases | |
| where no friendly timezone name is found (so far, just Opera). | |
| Device tested & works in: | |
| * IE 6, 7, 8, and 9 (latest versions of all) | |
| * Firefox 3 [through] 16 (16 = latest version to date) | |
| * Chrome 22 (latest version to date) | |
| * Safari 6 (latest version to date) | |
| * Mobile Safari on iOS 5 & 6 | |
| * Android 4.0.3 stock browser | |
| * Android 2.3.7 stock browser | |
| * IE Mobile 9 (WP 7.5) | |
| Known to fail in: | |
| * Opera 12 (desktop, latest version to date) | |
| For Opera, I've included (but commented out) a workaround spotted | |
| on StackOverflow that returns a GMT offset when no abbreviation is | |
| found. I haven't found a decent workaround. | |
| If you find any other cases where this method returns null or dodgy | |
| results, please say so in the comments; even if we can't find a | |
| workaround it'll at least help others determine if this approach is | |
| suitable for their project! | |
| */ | |
| var tzAbbr = function (dateInput) { | |
| var dateObject = dateInput || new Date(), | |
| dateString = dateObject + "", | |
| tzAbbr = ( | |
| // Works for the majority of modern browsers | |
| dateString.match(/\(([^\)]+)\)$/) || | |
| // IE outputs date strings in a different format: | |
| dateString.match(/([A-Z]+) [\d]{4}$/) | |
| ); | |
| if (tzAbbr) { | |
| // Old Firefox uses the long timezone name (e.g., "Central | |
| // Daylight Time" instead of "CDT") | |
| tzAbbr = tzAbbr[1].match(/[A-Z]/g).join(""); | |
| } | |
| // Uncomment these lines to return a GMT offset for browsers | |
| // that don't include the user's zone abbreviation (e.g., | |
| // "GMT-0500".) I prefer to have `null` in this case, but | |
| // you may not! | |
| // First seen on: http://stackoverflow.com/a/12496442 | |
| // if (!tzAbbr && /(GMT\W*\d{4})/.test(dateString)) { | |
| // return RegExp.$1; | |
| // } | |
| return tzAbbr; | |
| }; |
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I've found IE8 to return UTC, not GMT. Just got the date string below via BrowserStack's simulator. Might be worth checking for both. |
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On line #46 if:
tzAbbr[1].match(/[A-Z]/g)
returned null, you would have a javascript error.