function create_button(b) {
    b.innerHTML =
        '<span class="l"></span>' + 
        '<span class="c">' + b.innerHTML + '</span>' +
        '<span class="r"></span>';
}

window.addEvent('domready', function() {
    new Asset.css('/style/buttons.css', {}); 
    $$('a.button').each(create_button);
});