JS代码动态生成遮罩层、蒙层

　　　　　//父层级设置显示样式　
　　　　 document.getElementById("maskDiv").style.display = ‘block‘;
        //子节点设置样式var mask = document.createElement(‘div‘);
        mask.id = ‘maskDiv‘;  
        mask.style.width = window.innerWidth +‘px‘; 
        mask.style.height =  window.innerHeight +‘px‘;
        mask.style.background = ‘#000000‘;
        mask.style.opacity = ‘0.1‘; 
        mask.style.position = ‘absolute‘; 
        mask.style.display = ‘block‘; // 取消遮罩 设置为 none
        mask.style.top = 30+‘px‘;
        mask.style.zIndex = 999; // 设置元素层级
        document.body.appendChild(mask);

// 原文链接：https://blog.csdn.net/shihongji/article/details/81118937