function accordion(el) {
    if ($('visible') == el) {
        return;
    }
    if ($('visible')) {
        var eldown = el.parentNode.id+'-body';
        var elup = $('visible').parentNode.id+'-body';
        new Effect.BlindUp(elup, {duration:0.7});
        new Effect.BlindDown(eldown, {duration:0.7});
        $('visible').id = '';
    }
    el.id = 'visible';
}

function init() {

    // hide all elements apart from the one with id visible
    var acc = document.getElementById('accordion');
    var apanels = acc.getElementsByTagName('div');
    for (i = 0; i < apanels.length; i++) {
        if (apanels[i].className == 'panel_body') {
            apanels[i].style.display = 'none';
        }
    }
    var avis = document.getElementById('visible').parentNode.id+'-body';
    document.getElementById(avis).style.display = 'block';
}
function addEvent(elm, evType, fn, useCapture) {
    elm["on"+evType]=fn;return;
}

addEvent(window, "load", init);