Web页面仿Android Toast

//自定义弹框
function Toast(msg, duration) {
    duration = isNaN(duration) ? 1500 : duration;
    var m = document.createElement('div');
    m.innerHTML = msg;
    m.style.cssText = "width: 10%;min-width: 150px;opacity: 0.7;height: 30px;color: rgb(255, 255, 255);line-height: 30px;text-align: center;border-radius: 5px;position: fixed;top: 40%;left: 20%;z-index: 999999;background: rgb(0, 0, 0);font-size: 12px;";
    document.body.appendChild(m);
    setTimeout(function () {
        var d = 0.5;
        m.style.webkitTransition = '-webkit-transform ' + d + 's ease-in, opacity ' + d + 's ease-in';
        m.style.opacity = '0';
        setTimeout(function () { document.body.removeChild(m) }, d * 1000);
    }, duration);
}