遮罩层三

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
        <style type="text/css">
            span{
                display: inline-block;
                padding: 4px 12px;
                background: #E2E4E6;
                cursor: pointer;
            }
            #register{
                margin-left: 12px;
            }
            
            #mask{
                 100%;
                height: 2000px;
                background: #000000;
                opacity: 0.6;
                position: fixed;
                top: 0;
                left: 0;
                z-index: 1000;
                
                display: none;
            }
            
            #loginPage{
                position: fixed;
                top: 50%;
                left: 50%;
                transform: translate(-50%,-50%);
                z-index: 1100;
                
                display: none;
            }
            
            .loginMenu{
                box-sizing: border-box;
                height: 60px;
                padding-left: 15px;
                color: white;
                font-size: 20px;
                line-height: 60px;
                background: red;
            }
            
            .loginCon{
                box-sizing: border-box;
                height: 300px;
                 600px;
                color: white;
                text-align: center;
                position: relative;
                background: white;
                overflow: hidden;
                background: url(img/ba1c17be852740a74807a67531880caf.jpg) no-repeat;
                background-size: 100% 100%;
            }
            
            .loginCon div:first-of-type{
                margin-top: 100px;
            }
            
            .loginCon div:last-of-type{
                margin-top: 12px;
            }
            
            .loginCon input{
                height: 30px;
            }
            
            
            
            #close{
                display: inline-block;
                padding: 0;
                background: transparent;
                color: white;
                font-size: 24px;
                position: absolute;
                right: 20px;
                top: 15px;
                z-index: 1200s;
            }
        </style>
    </head>
    <body>
        <header>
            <span >登录</span>
            <span >注册</span>
        </header>
        <!--1. 演示遮罩层和弹出层-->
        <div >
            
        </div>
        <div >
            <div class="loginMenu">
                登录
            </div>
            <div class="loginCon">
                <div><label>用户名:</label><input type="text" name="username" /></div>
                <div><label>密&nbsp;&nbsp;&nbsp;码:</label><input type="password" name="password" /></div>
            </div>
            <span >X</span>
        </div>
    </body>
    <script type="text/javascript">
        //2. 使用js动态实现遮罩层和弹出层
        var login = document.getElementById('login');
        var register = document.getElementById('register');
        var mask = document.getElementById('mask');
        var loginPage = document.getElementById('loginPage');
        var close = document.getElementById('close');
        
        //点击登录创建遮罩层和登录框
        login.addEventListener('click',uLogin);
        
        //创建登录框
        function uLogin(){
            loginPage.style.display = "block";
            mask.style.display = "block";
            
            //点击关闭按钮关闭遮罩层和登录框
            var btnClose = document.getElementById('close');
            btnClose.addEventListener('click',closeLogin);
            
            //点击除登录框外的地方也可以关闭遮罩层和登陆框
            mask.addEventListener('click',closeLogin);
            
            function closeLogin(){
                loginPage.style.display = "none";
                mask.style.display = "none";
            }
            
        }
    </script>
</html>

遮罩层三