> I noticed there's some 255k js involved, a bit much for a simple contact form
fair point. the key here is enabling gzip-compression on the server, then its only a fraction of that size.
> Where can I read about this behaviour.js-file
it developed pretty much in parallel to the popular behaviour-script (http://bennolan.com/behaviour), but included some SS-specific stuff like Class-handling.
unfortunately its not fully documented, but you can have a look at the wiki[url].
customizing javascript-validation to use your own javascript is pretty easy: just selectively clear requirements in the init()-method of your controller and add your own stuff ([url=http://doc.silverstripe.com/doku.php?id=requirements]http://doc.silverstripe.com/doku.php?id=requirements).
class Page_Controller extends ContentController() {
function init() {
parent::init();
Requirements::clear('jsparty/prototype.js');
Requirements::javascript('mysite/javascript/yui.js');
// ...
}
}
of course you have to attach your own javascript-behaviour to the form/formfields this way.
the silverstripe-specific php-validation will still kick in though.