处于页面中间的alert

<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >
< html  xmlns ="http://www.w3.org/1999/xhtml" >
< head >
< meta  http-equiv ="Content-Type"  content ="text/html; charset=gb2312"   />
< title > 无标题文档 </ title >
< style  type ="text/css" >
<!--
#Layer1  {
    position : absolute ;
    width : 200px ;
    height : 115px ;
    z-index : 1 ;
}
-->
</ style >
</ head >

< body >
  < DIV  id =L1   style ="HEIGHT: 107px; LEFT: 341px; POSITION: absolute; TOP: 585px; WIDTH: 205px; Z-INDEX: 1" >
   < TABLE  bgColor =#ffffff  border =1  borderColorDark =#ffffff  borderColorLight =#000000  cellPadding =0  cellSpacing =0  width ="100%" >
                     < TR >
                       < TD  height =1  width =178 > □::阿里西西:: </ TD >
                       < TD  align =middle  onclick ="L1.style.visibility='hidden'"  
                      style ="CURSOR: hand"  width =21 > х </ TD ></ TR >
                     < TR  vAlign =top >
                       < TD  colSpan =2 
                         height =91 > 欢迎光临本站! < BR >< BR > 本站域名: < BR > http://www.k688.com 
                       </ TD ></ TR ></ TABLE ></ DIV >
< SCRIPT  LANGUAGE ="JavaScript" >
function  moveit()  // 这个函数用于把层放到浏览器中间
{
L1.style.left = ((document.body.offsetWidth - parseFloat (L1.style.width)) / 2 ) + document.body.scrollLeft;
L1.style.top = ((document.body.offsetHeight - parseFloat (L1.style.height)) / 2 ) + document.body.scrollTop;
}
window.onload = moveit;  // 网面打开时时执行moveit()
window.onresize = moveit;  // 当调整浏览器大小时执行moveit()
window.onscroll = moveit;  // 当拉动滚动条时执行moveit()
</ SCRIPT >

< a  href ="http://www.alixixi.com/Dev/HTML/jsrun/" > 欢迎访问阿里西西网页特效集 </ a >
< table  width ="280"  border ="1"  cellspacing ="0"  cellpadding ="0" >
   < tr >
     < td > &nbsp; </ td >
     < td > &nbsp; </ td >
   </ tr >
   < tr >
     < td >< div  id ="Layer1" > 是多少身份是东方士大夫 </ div ></ td >
     < td > &nbsp; </ td >
   </ tr >
</ table >

< script  type ="text/javascript"  language ="javascript" >
                
             function  sAlert(txt){
     var  eSrc = (document.all) ? window.event.srcElement:arguments[ 1 ];
     var  shield  =  document.createElement( " DIV " );
    shield.id  =   " shield " ;
    shield.style.position  =   " absolute " ;
    shield.style.left  =   " 0px " ;
    shield.style.top  =   " 0px " ;
    shield.style.width  =   " 100% " ;
    shield.style.height  =  document.body.scrollHeight + " px " ;
    shield.style.background  =   " #333 " ;
    shield.style.textAlign  =   " center " ;
    shield.style.zIndex  =   " 10000 " ;
    shield.style.filter  =   " alpha(opacity=0) " ;
    shield.style.opacity  =   0 ;
     var  alertFram  =  document.createElement( " DIV " );
    alertFram.id = " alertFram " ;
    alertFram.style.position  =   " absolute " ;
    alertFram.style.left  =   " 50% " ;
    alertFram.style.top  =   " 50% " ;
    alertFram.style.marginLeft  =   " -225px "  ;
    alertFram.style.marginTop  =   - 75 + document.documentElement.scrollTop + " px " ;
    alertFram.style.width  =   " 450px " ;
    alertFram.style.height  =   " 150px " ;
    alertFram.style.background  =   " #ccc " ;
    alertFram.style.textAlign  =   " center " ;
    alertFram.style.lineHeight  =   " 150px " ;
    alertFram.style.zIndex  =   " 10001 " ;

    strHtml   =   " <ul style="list-style:none;margin:0px;padding:0px;width:100%"> " ;
    strHtml  +=   "     <li style="background:#DD828D;text-align:left;padding-left:20px;font-size:14px;font-weight:bold;height:25px;line-height:25px;border:1px solid #F9CADE;">[系统提示]</li> " ;
    strHtml  +=   "     <li style="background:#fff;text-align:center;font-size:12px;height:120px;line-height:120px;border-left:1px solid #F9CADE;border-right:1px solid #F9CADE;"> " + txt + " </li> " ;
    strHtml  +=   "     <li style="background:#FDEEF4;text-align:center;font-weight:bold;height:25px;line-height:25px; border:1px solid #F9CADE;"><input type="button" value="确 定" id="do_OK" onclick="doOk()" /></li> " ;
    strHtml  +=   " </ul> " ;
    alertFram.innerHTML  =  strHtml;
    document.body.appendChild(alertFram);
    document.body.appendChild(shield);
     this .setOpacity  =   function (obj,opacity){
         if (opacity >= 1 )opacity = opacity / 100 ;
         try { obj.style.opacity = opacity; } catch (e){}
         try { 
             if (obj.filters.length > 0   &&  obj.filters( " alpha " )){
                obj.filters( " alpha " ).opacity = opacity * 100 ;
            } else {
                obj.style.filter = " alpha(opacity=" " + (opacity * 100 ) + " ") " ;
            }
        } catch (e){}
    }
     var  c  =   0 ;
     this .doAlpha  =   function (){
         if  ( ++ c  >   20 ){clearInterval(ad); return   0 ;}
        setOpacity(shield,c);
    }
     var  ad  =  setInterval( " doAlpha() " , 1 );
     this .doOk  =   function (){
         // alertFram.style.display = "none";
         // shield.style.display = "none";
        document.body.removeChild(alertFram);
        document.body.removeChild(shield);
        eSrc.focus();
        document.body.onselectstart  =   function (){ return   true ;}
        document.body.oncontextmenu  =   function (){ return   true ;}
    }
    document.getElementById( " do_OK " ).focus();
    eSrc.blur();
    document.body.onselectstart  =   function (){ return   false ;}
    document.body.oncontextmenu  =   function (){ return   false ;}
}
         </ script >
         < input  type ="button"  value ="点击这里"  onclick ="sAlert('我是一个渐变的sAlert',this);"   />
</ body >
</ html >