I have been really into JQuery the last few months. Can’t you tell? ^_^ Their plugins and documentation are amazing. I only wish I could quantify how much development time this framework has saved me. Not only does it reduce development time but it helps with the user experience by allowing manipulation of elements and allowing them to do things like drag and drop.

It is important to know that all JQuery plugins are tested for compatibility and currently have been tested in: IE 6.0+, FF 2+, Safari 3.1+, Opera 9.0+, and Google Chrome. You should always test for your target audience. That being said, I have never had the problem of a plugin or function not working properly in modern browsers.

One of my favorite plugins is the Datepicker. It is very simple to implement, yet very, very customizable. I have used this plugin in different projects. They look and act so different that if you were to visit each site (to the untrained eye) you could not tell they are the same code base.

Another very useful plugin that I use a lot is the Validate plugin. Again, we have an easy implementation. Use a selector and select your form. Let’s say we have a form with the ID of  “myForm” and we want to ensure that the fields are validated. Just add the following line and that’s it:

$("#myForm").validate(); - Simple, uh?

“A single line of jQuery to select the form and apply the validation plugin. And a bit of metadata on each element to specify the validation rules. Of course that isn’t the only way to specify rules. You also don’t have to rely on those default messages, but they come in handy when starting to setup validation for a form.” – Validator Documentation

There are a ton more plugins out there. These are just the ones I use most on my projects.

These, and a lot more of them, can be seen on their demo and documentation.