Countdown.js is a JavaScript library for calculating and displaying the timespan between two dates.

The library calculates the value continuously considering "the time goes on" and keeps generating an accurate output.

It can provide the timespan in many formats like milliseconds, seconds, minutes, hours, days, weeks and even millennias.

There are methods for displaying it as an English sentence like "3 years, 6 months, 21 days, 10 hours, and 32 minutes".

The countdown can be reset easily and there are callbacks both on start and end.

Moments.js is a feature-rich JavaScript library for working with dates (parsing, manipulating, and formatting them).

It works both in the browser and server with NodeJS as all code is compatible with both of the environments.

The library can easily convert any given date to many different formats, add/subtract dates, hours, etc. and has methods for displaying user-friendly date/times like "in 5 days"

Moment.js is multilanguage and any new languages can be easily added by editing a language file.

Timeglider is a jQuery plugin for displaying any number of events in a highly-flexible timeline.

Its interface has support for zooming in/out (mouse wheel can be used too) and panning where you can quickly navigate through the time and find events.

Events are clickable and can display a detailed view of them inside a modal box.

JSON is used as the data source for the items in the timeline. Within the data source, it is possible to attach items to categories for filtering them (filtering can also be done keyword-based).

There are also many other features like "the ability to use images in the timeline", "attaching icons to events, "setting an importance for each item" and more.

wdCalendar is a jQuery plugin that enables us to create an event calendar that functions similar to the popular Google Calendar.

With a drag'n drop interface and feature-rich API, it is possible to create, update or delete events easily.

It has custom views for day, week or month where you can easily go to a selected date (also with the help of provided JS methods).

Usually, multi-day events are complicated, however, wdCalendar handles them well.

P.S. The resource website also shares other useful plugins for a tree menu display, date-picker and more.

jTrack is a time tracking application that is built with jQuery and works without SQL, sessions or cookies.

It rather uses the localStorage with the help of DOMCached and jquery-json plugins.

The application enables you to add any number of tasks and starts tracking the time for each when a "start" button is clicked.

jTrack is a pretty simple tracker which is suitable to be integrated into other applications or tracking the time in the most plain way.

Also, it is a good resource to see "how localStorage can be used with jQuery".

Any+Time is a feature-rich jQuery plugin (has a PrototypeJS version too) for creating simple-to-advanced date and time pickers.

It can work as a pop-up or an always present picker, can be set as a time or date only picker and supports:

• 12/24 hour clock
• any custom date format
• date/time range limits
• custom start day of the week
• UTC offsets / time zones
• and more.

Any+Time can be customized with custom labels and languages. Also, it can be styled completely via CSS or with the help of jQuery UI ThemeRoller.

Using the plugin, you can easily convert dates to/from strings (including JSON and XML) and it supports multiple instances in a single page.

It is keyboard-friendly (WAI-ARIA 1.0) and, optionally, can respond to double clicks.

CalendarPicker is a jQuery plugin that enables us to create a good-looking and pretty original date picker.

It displays a pre-defined amount of the next and previous days/months/years for a quick selection.

Also, users can browse through the dates with mouse-wheel (uses the mouse wheel plugin) or the prev/next buttons.

The date picker can display the current date by default or any selected one on load.

Day and month names can be optionally customized which is nice for multilingual interfaces.

jsDatePick is a very easy-to-implement JavaScript date picker.

It can appear by clicking an input field or directly appended into the target element and can be browsed quickly as months or years.

The picker can be set to display a range of years or limited to today's date. And, a selected date can be passed within the parameters which is useful when editing a date field.

jsDatePick comes with ~10 color schemes where new ones can be created.

Ajax Availability Calendar is an open source PHP application for displaying the availability of an item (hotel room, appointment, etc.).

It comes with an Ajaxed administration panel (multiple admin users are supported) to manage the calendar.

The application is multilingual & unlimited number of items can be added under multiple languages.

Months displayed are changed with Ajax requests where no refreshes are required & it can be totally styled via CSS.

Calender Eightysix is an unobtrusive calendar & datepicker that is built with MooTools.

It offers a very easy-to-use navigation for jumping back / forth between months, years & decades without drop-down boxes.

The script is lightweight (9.5kb) & can be themed via CSS (3 themes are already included).

It has a bunch of options for maximum customization like setting:

• default date on load
• min-max dates of the calendar
• date format
• unpickable days/weeks
• durations between slides, fades, toggles
• the calendar start date (Monday – Sunday)
• & more..

P.S. It is also the successor of the popular Vista-like Ajax Calendar (WRD post).