//= require modernizr // By @mathias, based on mths.be/axh Modernizr.addTest('details', function() {

var doc = document,
    el = doc.createElement('details'),
    fake,
    root,
    diff;
if (!('open' in el)) { // return early if possible; thanks @aFarkas!
    return false;
}
root = doc.body || (function() {
    var de = doc.documentElement;
    fake = true;
    return de.insertBefore(doc.createElement('body'), de.firstElementChild || de.firstChild);
}());
el.innerHTML = '<summary>a</summary>b';
el.style.display = 'block';
root.appendChild(el);
diff = el.offsetHeight;
el.open = true;
diff = diff != el.offsetHeight;
root.removeChild(el);
fake && root.parentNode.removeChild(root);
return diff;

});