Mootools code

var Card = new Class({

    Implements: [Options, Events],
    
    options: {
        index: 0,
        bg: null,
        onMouseenter: doRollOver,
        onMouseleave: doRollOut
    },
    
    initialize: function(options){
        this.setOptions(options);
    },
    
    doRollOver: function(){
        alert("over");
    },
    
    doRollOut: function(){
        alert("out");
    }
    
});



window.addEvent('domready', function(){
    $$('.card').each(function(element, index){
        element = new Card({
            index: index,
            bg: element.getChildren('.cardBG')
        });
    });
});