Merge pull request #1121 from edx/dhm/timezone_display

Replace date lib w/ simpler tzAbbr

cms/static/js/views/settings/main_settings_view.js

@@ -33,8 +33,7 @@ CMS.Views.Settings.Details = CMS.Views.ValidatingView.extend({
             $(this).show();
         });
 
-        var dateIntrospect = new Date();
-        this.$el.find('#timezone').html("(" + dateIntrospect.getTimezone() + ")");
+        this.$el.find('#timezone').html("(" + tzAbbr() + ")");
 
         this.listenTo(this.model, 'invalid', this.handleValidationError);
         this.listenTo(this.model, 'change', this.showNotificationBar);

cms/templates/settings.html

@@ -14,7 +14,7 @@ from contentstore import utils
   <link rel="stylesheet" type="text/css" href="${static.url('js/vendor/timepicker/jquery.timepicker.css')}" />
   <script src="${static.url('js/vendor/timepicker/jquery.timepicker.js')}"></script>
   <script src="${static.url('js/vendor/timepicker/datepair.js')}"></script>
-  <script src="${static.url('js/vendor/date.js')}"></script>
+  <script src="${static.url('js/vendor/tzAbbr.js')}"></script>
 
   <script type="text/javascript" src="${static.url('js/models/course_relative.js')}"></script>
   <script type="text/javascript" src="${static.url('js/views/validating_view.js')}"></script>

common/static/js/vendor/tzAbbr.js

+/* 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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