function turn(elem) {
var cls = elem.className;
if (/front/.test('front')) {
cls = cls.replace(/front/, 'back');
} else {
cls = cls.replace(/back/, 'front'); // back爲正則表達式
}
elem.className = cls;//很經典的代碼
}
function turn(elem) {
var cls = elem.className;
if (/front/.test('front')) {
cls = cls.replace(/front/, 'back');
} else {
cls = cls.replace(/back/, 'front'); // back爲正則表達式
}
elem.className = cls;//很經典的代碼
}
(function(d, s, id) { let js, fjs = d.getElementsByTagName(s)[0]; if (d.getElementById(id)) retur