web页面弹窗遮罩层

 <script type="text/javascript">
       var docEle = function() {
           return document.getElementById(arguments[0]) || false;
       }

       function openNewDiv(_id) {
           var m = "mask";
           if (docEle(_id)) document.body.removeChild(docEle(_id));
           if (docEle(m)) document.body.removeChild(docEle(m));

           //mask遮罩层

           var newMask = document.createElement("div");
           newMask.id = m;
           newMask.style.position = "absolute";
           newMask.style.zIndex = "1";
           _scrollWidth = Math.max(document.body.scrollWidth, document.documentElement.scrollWidth);
           _scrollHeight = Math.max(document.body.scrollHeight, document.documentElement.scrollHeight);
           newMask.style.width = _scrollWidth + "px";
           newMask.style.height = _scrollHeight + "px";
           newMask.style.top = "0px";
           newMask.style.left = "0px";
           newMask.style.background = "#33393C";
           newMask.style.filter = "alpha(opacity=40)";
           newMask.style.opacity = "0.40";
           document.body.appendChild(newMask);

           //新弹出层

           var newDiv = document.createElement("div");
           newDiv.id = _id;
           newDiv.style.position = "absolute";
           newDiv.style.zIndex = "9999";
           newDivWidth = 400;
           newDivHeight = 200;
           newDiv.style.width = newDivWidth + "px";
           newDiv.style.height = newDivHeight + "px";
           newDiv.style.top = (document.body.scrollTop + document.body.clientHeight / 2 - newDivHeight / 2) + "px";
           newDiv.style.left = (document.body.scrollLeft + document.body.clientWidth / 2 - newDivWidth / 2) + "px";
           newDiv.style.background = "#EFEFEF";
           newDiv.style.border = "1px solid #860001";
           newDiv.style.padding = "5px";
           newDiv.innerHTML = "弹出层内容 ";

           document.body.appendChild(newDiv);

           //弹出层滚动居中

           function newDivCenter() {
               newDiv.style.top = (document.body.scrollTop + document.body.clientHeight / 2 - newDivHeight / 2) + "px";
               newDiv.style.left = (document.body.scrollLeft + document.body.clientWidth / 2 - newDivWidth / 2) + "px";
           }
           if (document.all) {
               window.attachEvent("onscroll", newDivCenter);
           }
           else {
               window.addEventListener('scroll', newDivCenter, false);
           }

           //关闭新图层和mask遮罩层

           var newA = document.createElement("a");
           newA.href = "#";
           newA.innerHTML = "关闭";
           newA.onclick = function() {
               if (document.all) {
                   window.detachEvent("onscroll", newDivCenter);
               }
               else {
                   window.removeEventListener('scroll', newDivCenter, false);
               }
               document.body.removeChild(docEle(_id));
               document.body.removeChild(docEle(m));
               return false;
           }
           newDiv.appendChild(newA);
       }
</script>

 

调用<a onclick="openNewDiv('newDiv');return false;" style="cursor:pointer">显示弹层</a>