js的alert样式如何更改如背景颜色

复制代码代码如下:

window.alert = function(str)

{

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";

//弹出对话框时的背景颜色

shield.style.background = "#fff";

shield.style.textAlign = "center";

shield.style.zIndex = "25";

//背景透明 IE有效

//shield.style.filter = "alpha(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 = "-75px";

alertFram.style.width = "450px";

alertFram.style.height = "150px";

alertFram.style.background = "#ff0000";

alertFram.style.textAlign = "center";

alertFram.style.lineHeight = "150px";

alertFram.style.zIndex = "300";

strHtml = "<ul style=/"list-style:none;margin:0px;padding:0px;width:100%/">/n";

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;/">[自定义提示]</li>/n";

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;/">"+str+"</li>/n";

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/" onclick=/"doOk()/" /></li>/n";

strHtml += "</ul>/n";

alertFram.innerHTML = strHtml;

document.body.appendChild(alertFram);

document.body.appendChild(shield);

var ad = setInterval("doAlpha()",5);

this.doOk = function(){

alertFram.style.display = "none";

shield.style.display = "none";

}

alertFram.focus();

document.body.onselectstart = function(){return false;};

}

效果如图