CSS自定義彈出框

<script type="text/javascript" language="javascript"> 
function sAlert(str){ 
var msgw,msgh,bordercolor; 
msgw=400;//提示窗口的寬度 
msgh=100;//提示窗口的高度 
titleheight=25//提示窗口標題高度 
bordercolor="#336699";//提示窗口的邊框顏色 
titlecolor="#99CCFF";//提示窗口的標題顏色 
var sWidth,sHeight; 
sWidth=document.body.offsetWidth;//瀏覽器工作區域內頁面寬度 或使用 screen.width//屏幕的寬度 
sHeight=screen.height;//屏幕高度（垂直分辨率） 
//背景層（大小與窗口有效區域相同，即當彈出對話框時，背景顯示為放射狀透明灰色） 
var bgObj=document.createElement("div");//創建一個div對象（背景層） //動態創建元素，這里創建的是 div 
//定義div屬性，即相當於(相當於，但確不是，必須對對象屬性進行定義 
//<div id="bgDiv" style="position:absolute; top:0; background-color:#777; filter:progid:DXImagesTransform.Microsoft.Alpha(style=3,opacity=25,finishOpacity=75); opacity:0.6; left:0; width:918px; height:768px; z-index:10000;"></div> 
bgObj.setAttribute('id','bgDiv'); 
bgObj.style.position="absolute"; 
bgObj.style.top="0"; 
bgObj.style.background="#777"; 
bgObj.style.filter="progid:DXImageTransform.Microsoft.Alpha(style=3,opacity=25,finishOpacity=75"; 
bgObj.style.opacity="0.6"; 
bgObj.style.left="0"; 
bgObj.style.width=sWidth + "px"; 
bgObj.style.height=sHeight + "px"; 
bgObj.style.zIndex = "10000"; 
document.body.appendChild(bgObj);//在body內添加該div對象 
//創建一個div對象（提示框層） 
var msgObj=document.createElement("div") 
//定義div屬性，即相當於 
//<div id="msgDiv" align="center" style="background-color:white; border:1px solid #336699; position:absolute; left:50%; top:50%; font:12px/1.6em Verdana,Geneva,Arial,Helvetica,sans-serif; margin-left:-225px; margin-top:npx; width:400px; height:100px; text-align:center; line-height:25px; z-index:100001;"></div> 
msgObj.setAttribute("id","msgDiv"); 
msgObj.setAttribute("align","center"); 
msgObj.style.background="white"; 
msgObj.style.border="1px solid " + bordercolor; 
msgObj.style.position = "absolute"; 
msgObj.style.left = "50%"; 
msgObj.style.top = "50%"; 
msgObj.style.font="12px/1.6em Verdana, Geneva, Arial, Helvetica, sans-serif"; 
msgObj.style.marginLeft = "-225px" ; 
msgObj.style.marginTop = -75+document.documentElement.scrollTop+"px"; 
msgObj.style.width = msgw + "px"; 
msgObj.style.height =msgh + "px"; 
msgObj.style.textAlign = "center"; 
msgObj.style.lineHeight ="25px"; 
msgObj.style.zIndex = "10001"; 
var title=document.createElement("h4");//創建一個h4對象（提示框標題欄） 
//定義h4的屬性，即相當於 
//<h4 id="msgTitle" align="right" style="margin:0; padding:3px; background-color:#336699; filter:progid:DXImageTransform.Microsoft.Alpha(startX=20, startY=20, finishX=100, finishY=100,style=1,opacity=75,finishOpacity=100); opacity:0.75; border:1px solid #336699; height:18px; font:12px Verdana,Geneva,Arial,Helvetica,sans-serif; color:white; cursor:pointer;" onclick="">關閉</h4> 
title.setAttribute("id","msgTitle"); 
title.setAttribute("align","right"); 
title.style.margin="0"; 
title.style.padding="3px"; 
title.style.background=bordercolor; 
title.style.filter="progid:DXImageTransform.Microsoft.Alpha(startX=20, startY=20, finishX=100, finishY=100,style=1,opacity=75,finishOpacity=100);"; 
title.style.opacity="0.75"; 
title.style.border="1px solid " + bordercolor; 
title.style.height="18px"; 
title.style.font="12px Verdana, Geneva, Arial, Helvetica, sans-serif"; 
title.style.color="white"; 
title.style.cursor="pointer"; 
title.innerHTML="關閉"; 
title.onclick=removeObj; 
var button=document.createElement("input");//創建一個input對象（提示框按鈕） 
//定義input的屬性，即相當於 
//<input type="button" align="center" style="width:100px; align:center; margin-left:250px; margin-bottom:10px;" value="關閉"> 
button.setAttribute("type","button"); 
button.setAttribute("value","關閉"); 
button.style.width="60px"; 
button.style.align="center"; 
button.style.marginLeft="250px"; 
button.style.marginBottom="10px"; 
button.style.background=bordercolor; 
button.style.border="1px solid "+ bordercolor; 
button.style.color="white"; 
button.onclick=removeObj; 
function removeObj(){//點擊標題欄觸發的事件 
   document.body.removeChild(bgObj);//刪除背景層Div 
   document.getElementById("msgDiv").removeChild(title);//刪除提示框的標題欄 
   document.body.removeChild(msgObj);//刪除提示框層 
} 
document.body.appendChild(msgObj);//在body內添加提示框div對象msgObj 
document.getElementById("msgDiv").appendChild(title);//在提示框div中添加標題欄對象title 
var txt=document.createElement("p");//創建一個p對象（提示框提示信息） 
//定義p的屬性，即相當於 
//<p style="margin:1em 0;" id="msgTxt">測試效果</p> 
txt.style.margin="1em 0" 
txt.setAttribute("id","msgTxt"); 
txt.innerHTML=str;//來源於函數調用時的參數值 
document.getElementById("msgDiv").appendChild(txt);//在提示框div中添加提示信息對象txt 
document.getElementById("msgDiv").appendChild(button);//在提示框div中添加按鈕對象button 
} 
</script>