jQuery Spinner is lightweight implementation of a spinner for selecting numbers by clicking +/– or by typing.
Supports validation, arrow keys, min and max constraints and is unobtrusive.
Verify.js is a powerful, customizable asynchronous form validation library.
Ingrid is an unobtrusive jQuery component that adds datagrid behaviors as column resizing, paging, sorting, row and column styling, and more to your tables.
An alert alternative for jQuery that looks good. Apprise is a very simple, fast, attractive, and unobtrusive way to communicate with your users. Also, this gives you complete control over style, content, position, and functionality.
The jQuery Form Plugin allows you to easily and unobtrusively upgrade HTML forms to use AJAX. The main methods, ajaxForm and ajaxSubmit, gather information from the form element to determine how to manage the submit process. Both of these methods support numerous options which allows you to have full control over how the data is submitted.