The Best JavaScript Library

I am in the process of creating a new web application using mvc and I am trying to choose the best JavaScript library to use.  I am pretty much sure that I am going to go with jQuery but nonetheless I wanted to review the libraries out there.  One reason is that I am writing a book and I want to be able to justify to the readers why I am going with jQuery and not the others.

What do I want from my JavaScript Library?

I want it to be easy (I am not a JavaScript expert)
I want it to be small
I want it to be fast
I want it to be extensible
I want good documentation and/or community support
I want good/easy AJAX support
I want it to be
I also want it to be testable (I am using TDD for this project/book)
Open Source would be nice but not required

What are my options?

jQuery –
Microsoft AJAX –
Dojo –
Prototype –

This is a shortlist but if you want a more exhaustive, read this.  I only picked these, for the simple reasons that I have heard of them and are somewhat known by the community.

3 days later

It’s been 3 days since I started this post and I have spent all that time playing around with these libraries…  I have gone back and forth in my opinion on which library to use.  I love jQuery’s selectors, ease of use and community support.  Porototype is also very popular and somewhat similar to jQuery; but I would take jQuery over Prototype for the simple reason that I like jQuery.  YUI (Yahoo! UI) library is beautiful looking and very comprehensive.



  1. Ease to learn and use
  2. Beautiful syntax (the least typing)
  3. Great community support and lots of fans
  4. Decent Documentation
  5. I already own the book
  6. QUnit test framework (


  1. UI isn’t that great
  2. Library is not as full-featured without plugins
  3. Plugins are somewhat inconsistent in quality depending on the author



  1. Good documentation
  2. Good community support
  3. Lots of books
    1. Practical Prototype and
    2. Prototype and You Never Knew JavaScript Could Do This!
    3. and many more…
  4. Great UI with the add-on (


  1. Couldn’t find a testing framework (but I didn’t look too hard)
  2. For some purely emotional reason, I prefer jQuery



  1. Great UI components and styles
  2. The best documented library out there, hands down.
  3. Distributed hosting of JS files – the script files will be downloaded from Yahoo server, so when my site becomes a mega-hit, it will scale better.
  4. Great test framework and test runner – check these demos
  5. The most complete library
  6. PDF cheat sheets for every component


  1. Very verbose – not as elegant as jQuery, but that’s not too hard to fix e.g. I can assign YAHOO.util.Event to a variable $E and use $E as the shorthand.

The rest

I got tired of all the research and decided to wrap it up, so I glanced over Microsoft AJAX and Dojo and realized that there isn’t enough there to justify more research.

The winner…

When I started this post, I was pretty certain my final choice will be jQuery.  Then I started playing with Prototype and it looked really good, which kind of opened my eyes to the need to be open minded and objective.  This lead to a more objective look at YUI and the conclusion to use YUI.  I was very impressed with YUI’s look & feel, extensive documentation, testing framework and the icing on the cake was the free hosting of the JavaScript libraries.  This was a really tough decision because I still love jQuery the best.

[poll id=”2″]