当Top2出现时候，希望右侧出现滚动条，并且可用
------------------------------------------js
<script>
$(function () {
$('.Top1').mousewheel(function () {
$('.Top1').addClass("G");
})
})
</script>
---------------------------------------------css
<style>
body {
overflow: hidden;
margin: 0px;
}
.Top1 {
position: absolute;
width: 100%;
height: 100%;
overflow: visible !important;
background: #020202;
transform-style: preserve-3d;
transform: translate3d(0,0,0);
transition: all ease 1s;
}
.G {
transform: translate3d(0,-100%,0);
}
.Top2 {
width: 100%;
position: absolute;
height: 5000px;
z-index:-10;
top: 0px;
background: #ffd800;
overflow:visible !important;
}
</style>
-------------------------------------------html
<body>
<div class="Top1"></div>
<div class="Top2">
<h1>555555</h1>
</div>
</body>