以下为引用的内容：

网页教学网Webjx.Com 提供最新最快的网页技术

*{

margin:0;padding:0;

}

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  = "

• \n";

strHtml += "

[系统提示]\n";

strHtml += "

"+txt+"\n";

strHtml += "

\n";

strHtml += "

\n";

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;}

}