dropbox-folder-size.js

javascript:
	(function() {
		var kb = Object.values(BrowseFile._file_index).reduce(function(kb, file) {
			return kb + file.bytes/1000;
		}, 0);
		var units = ['kb', 'mb', 'gb', 'tb'], unit = units.shift(), size = kb;
		for (var i=0; i<3; i++) {
			if (size < 1000) {
				break;
			}
			size /= 1000;
			unit = units.shift();
		}
		alert('Folder size: ' + (Math.round(size*1000)/1000) + ' ' + unit);
	})();
	void();