JavaScript library feedback

[Wolfy87]

Hey, I have been working on my own JavaScript library, Spark, for about three months now and I feel I have got it to a respectable standard.
Without a user base however I have no way of knowing what I need to improve.

I was wondering if anyone could give it a little go and tell me what you think, whats bad, whats good or what you would like to see.
I set up a website for it with a download and documentation section.

It can do all sorts including AJAX, JSON encoding / decoding and animation.
For example, you can load a file and fade it in like so.

// Spark.ajax(method, file, arguments, callback (makes call async));
Spark.ajax('get', 'somefile.txt', false, function(data) {
    // Add the content and fade in (chainable functions)
    Spark('p.target')
        .content(data)
        .transition('fadein');
});

I have attached v1.4.6, which is the latest at the time of writing.

Any comments other than 'give up' are welcome. Thank you.

EDIT

You can view a working version of the above example on jsFiddle.
You can also use this PDF I wrote as a reference, it talks you through pretty much everything.