vue遮罩层如何阻止滚动

<div class="popup" @mousewheel="mousewheel">
   <div class="cen">弹框内容</div>
</div>

mousewheel(e){
  e.preventDefault();
}

<div class="popup" @touchmove.prevent v-if="show">
</div>

<!-- 手写弹框 -->
    // 遮罩层
    <div class="popup" @touchmove.prevent v-if="show"></div>
    
    // 弹框内容 (已设置overflow:scroll超出滚动)
    <div class="cen" v-if="show">
        <ul>
            <li v-for="(e,i) in dts" :key="i">
                <img :src="e" alt="">
            </li>
        </ul>
    </div>
    // 关闭按钮
    <div class="gb" @click="gb()" v-if="show">
        <svg t="1604306237286" class="icon ic" viewBox="0 0 1024 1024" version="1.1" xmlns="http://www.w3.org/2000/svg" p-id="2388" width="48" height="48"><path d="M660.518 682.87c-5.903 0-11.804-2.2-16.306-6.702L342.366 374.372c-9.003-9.003-9.003-23.608 0-32.61s23.608-9.002 32.61 0l301.847 301.796c9.002 9.003 9.002 23.607 0 32.61-4.501 4.5-10.404 6.703-16.305 6.703z" p-id="2389" fill="#ffffff"></path><path d="M358.67 682.87c-5.901 0-11.803-2.2-16.304-6.702-9.003-9.003-9.003-23.607 0-32.61l301.846-301.796c9.003-9.002 23.607-9.002 32.61 0 9.002 9.002 9.002 23.607 0 32.61L374.977 676.168c-4.503 4.5-10.404 6.703-16.307 6.703z" p-id="2390" fill="#ffffff"></path><path d="M509.62 956.157c-246.579 0-447.244-200.614-447.244-447.242 0-246.58 200.664-447.218 447.243-447.218 246.58 0 447.243 200.638 447.243 447.218 0 246.628-200.664 447.242-447.243 447.242z m0-848.346c-221.172 0-401.13 179.933-401.13 401.105 0 221.169 179.958 401.128 401.13 401.128 221.17 0 401.127-179.959 401.127-401.128 0-221.172-179.957-401.105-401.128-401.105z" p-id="2391" fill="#ffffff"></path></svg>
    </div>

// 这是列表数据点击时
details(e)
{
   this.dts=e
   this.show=!this.show
   var body = document.getElementsByTagName('body')[0]
   console.log(body)
   body.style.overflow='hidden'
}, 
// 这是点击关闭按钮时
gb()
{
   this.show=!this.show
   var body = document.getElementsByTagName('body')[0]
   console.log(body)
   body.style.overflow=null
}

<div class="dialog" @touchmove.prevent ></div>