/**

Thanks to jozilla.net (Jo Vermeulen)

*/
var theRules = {
    'div.abstract_toggle' : function(el){
        el.onclick = function(){
            var abstract =  this.next();

            if (Element.hasClassName(this, 'open')) {
                // it's invisible
                
                // make visible
                Effect.toggle(abstract, 'blind');
                
                // toggle button
                Element.addClassName(this, 'close');
                Element.removeClassName(this, 'open');
            } else {
                // it's visible
                
                // make invisible
                Effect.toggle(abstract, 'blind');
                
                // toggle button
                Element.addClassName(this, 'open');
                Element.removeClassName(this, 'close');
            }
        }       
    }
};

Behaviour.register(theRules);
Behaviour.addLoadEvent(hideAbstracts);

function hideAbstracts()
{
    abstracts = document.getElementsByClassName('abstract');
    abstract_toggles = document.getElementsByClassName('abstract_toggle');

    // hide abstracts
    for (i = 0; i < abstracts.length; i++) {
        Element.toggle(abstracts[i]);
    }

    // set to open button
    for (i = 0; i < abstract_toggles.length; i++) {
        Element.addClassName(abstract_toggles[i], 'open');
    }
}