css弹出框 提示信息

<style type="text/css">#alertBox{ position:absolute; display:none; width:100%; height:100%; left:0px; top:0px; z-index:99; background: rgba(255, 255, 255, 0.1);}#alertBox #alertBoxShadow{ position:absolute; width:200px; height:auto; left:50%; top:50%; margin-left:-100px; margin-top:-80px; background: rgba(255, 255, 255, 0.9); background-size: 100% 100%; z-index:100; padding-bottom:30px;}#alertBox #text{ margin:20px; font-size:1.0em;}#alertBox #alertBoxBtn{ position:absolute; right:10%; bottom:10px; width:78px; height:26px; background: url("../img/ChoiceBtn.png") no-repeat; background-size: 100% 100%;}</style>        <script type="text/javascript">function CloseBox(){       document.getElementById('alertBox').style.display="none";}function alertBox(value){document.getElementById('alertBox').style.display="block";//alert(value);document.getElementById('text').innerHTML=value;}</script><div id="alertBox"><div id="alertBoxShadow">        <div id="text"></div>        <button id="alertBoxBtn" onClick="CloseBox();">确定</button>    </div></div>