JS遮罩层

HTML：

<input id="Button1" type="button" value="点击弹出层" onclick="ShowDiv('MyDiv','fade')" />
    <!--弹出层时背景层DIV-->
    <div id="fade" class="black_overlay">
    </div>
    <div id="MyDiv" class="white_content">
        <div style="text-align: right; cursor: default; height: 40px;">
            <br />
            <span style="font-size: 16px;" onclick="CloseDiv('MyDiv','fade')">关闭</span>
        </div>
        遮罩层。
    </div>
    <br />
    <center>
        层的遮罩效果</center>

CSS样式：

<style type="text/css">
        .black_overlay
        {
            display: none;
            position: absolute;
            top: 0%;
            left: 0%;
            width: 100%;
            height: 100%;
            background-color: black;
            z-index: 1001;
            -moz-opacity: 0.8;
            opacity: .80;
            filter: alpha(opacity=80);
        }
        .white_content
        {
            display: none;
            position: absolute;
            top: 10%;
            left: 10%;
            width: 80%;
            height: 80%;
            border: 16px solid lightblue;
            background-color: white;
            z-index: 1002;
            overflow: auto;
        }
        .white_content_small
        {
            display: none;
            position: absolute;
            top: 20%;
            left: 30%;
            width: 40%;
            height: 50%;
            border: 16px solid lightblue;
            background-color: white;
            z-index: 1002;
            overflow: auto;
        }
    </style>

JS代码：

<script type="text/javascript">
        //弹出隐藏层
        function ShowDiv(show_div, bg_div) {
            document.getElementById(show_div).style.display = 'block';
            document.getElementById(bg_div).style.display = 'block';
            var bgdiv = document.getElementById(bg_div);
            bgdiv.style.width = document.body.scrollWidth;
            // bgdiv.style.height = $(document).height();
            $("#" + bg_div).height($(document).height());
        };
        //关闭弹出层
        function CloseDiv(show_div, bg_div) {
            document.getElementById(show_div).style.display = 'none';
            document.getElementById(bg_div).style.display = 'none';
        };
    </script>

遮罩层效果：

自动弹出一个div：

<style type="text/css">
#white_content{
    display: none;
    position:fixed;
    top:0%;
    left:0%;
    width: 100%;
    background-color:black;
    z-index: 1002;
    opacity: .50;
    overflow: auto;}
    
</style>

<script language="javascript">
    function test(){
        var div = document.getElementById('white_content');
        div.style.display = "block";}
        //$('html,body').animate({scrollTop: '0px'}, 100);}
            window.onload=function(){
        setTimeout("test()",2000);}//两秒钟弹出div
        
</script>

 点击弹出/关闭罩层

<script language="javascript">
    function text(id){
        var div = document.getElementById(id);
        if(white.style.display=='block')
        {
            white.style.display='none';}
        else{
            white.style.display='block';}
        }

</script>