.alertTips{position:fixed;top:50%;left:50%;margin-left:-150px;padding:15px;width:300px;line-height:21px;font-size:15px;box-sizing:border-box;background-color:rgba(0,0,0,0.7);text-align:center;border-radius:3px;color:#fff;-moz-transform:translateY(-50%) scale(0);-ms-transform:translateY(-50%) scale(0);-webkit-transform:translateY(-50%) scale(0);transform:translateY(-50%) scale(0);-moz-transition:-moz-transform .2s linear;-o-transition:-o-transform .2s linear;-webkit-transition:-webkit-transform .2s linear;transition:transform .2s linear;z-index:10000}.alertTips.show{-moz-transform:translateY(-50%) scale(1);-ms-transform:translateY(-50%) scale(1);-webkit-transform:translateY(-50%) scale(1);transform:translateY(-50%) scale(1)}