【JavaScript】点击页面上的按纽，弹出一个层，背景变灰
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>点击页面上的按纽，弹出一个层，背景变灰</title>
<script type="text/javascript" src="js/newDiv.js"></script>
<meta http-equiv= "Content-Type " content= "text/html; charset=gb2312 " />
</head>
<body>
<p >点击页面上的按纽，弹出一个层，背景变灰</p>
<input type= "button" onclick= " sAlert( '测试效果 <br/> 嗯！效果还不错！ '); " value="点击这里 " />
<input type="button" value="test" />
</body>
</html>
<script language="JavaScript">
function sAlert(str)
{
var msgw,msgh,bordercolor;
msgw=400;//提示窗口的宽度
msgh=100;//提示窗口的高度
titleheight=25 //提示窗口标题高度
bordercolor= "#336699 ";//提示窗口的边框颜色
titlecolor= "#99CCFF ";//提示窗口的标题颜色
var sWidth,sHeight;
sWidth=document.body.offsetWidth;//浏览器工作区域内页面宽度
sHeight=screen.height;//屏幕高度（垂直分辨率）
//背景层（大小与窗口有效区域相同，即当弹出对话框时，背景显示为放射状透明灰色）
var bgObj=document.createElement( "div ");//创建一个div对象（背景层）
//定义div属性，即相当于
// <div bgDiv " position:absolute; top:0; background-color:#777; filter:progid:DXImagesTransform.Microsoft.Alpha(> </div>
bgObj.setAttribute( 'id ', 'bgDiv ');
bgObj.style.position="absolute";
bgObj.style.top= "0";
bgObj.style.background= "#777 ";
bgObj.style.filter= "progid:DXImageTransform.Microsoft.Alpha(;
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内添加该div对象
var msgObj=document.createElement( "div")//创建一个div对象（提示框层）
//定义div属性，即相当于
//<div msgDiv " align= "center " 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.1px solid " ;
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");//创建一个h4对象（提示框标题栏）
//定义h4的属性，即相当于
// <h4 msgTitle " align= "right " margin:0; padding:3px; background-color:#336699; filter:progid:DXImageTransform.Microsoft.Alpha(startX=20, startY=20, finishX=100, finishY=100, onclick= " "> 关闭 </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,;
title.style.opacity= "0.75 ";
title.style.1px solid" ;
title.style.height= "18px ";
title.style.font= "12px Verdana, Geneva, Arial, Helvetica, sans-serif";
title.style.color= "white";
title.style.cursor= "pointer";
title.innerHTML= "关闭";
title.onclick=removeObj;
var button=document.createElement( "input");//创建一个input对象（提示框按钮）
//定义input的属性，即相当于
// <input type= "button " align= "center " width:100px; align:center; margin-left:250px; margin-bottom:10px; " value= "关闭 ">
button.setAttribute( "type", "button");
button.setAttribute( "value", "关闭");
button.style.width= "60px";
button.style.align= "center";
button.style.marginLeft= "250px";
button.style.marginBottom= "10px";
button.style.background=bordercolor;
button.style.1px solid";
button.style.color= "white";
button.onclick=removeObj;
function removeObj()
{//点击标题栏触发的事件
document.body.removeChild(bgObj);//删除背景层Div
document.getElementById( "msgDiv").removeChild(title);//删除提示框的标题栏
document.body.removeChild(msgObj);//删除提示框层
}
document.body.appendChild(msgObj);//在body内添加提示框div对象msgObj
document.getElementById( "msgDiv").appendChild(title);//在提示框div中添加标题栏对象title
var txt=document.createElement( "p");//创建一个p对象（提示框提示信息）
//定义p的属性，即相当于
// <p margin:1em 0; " msgTxt "> 测试效果 </p>
txt.style.margin= "1em 0"
txt.setAttribute( "id ", "msgTxt");
txt.innerHTML=str;//来源于函数调用时的参数值
document.getElementById( "msgDiv").appendChild(txt);//在提示框div中添加提示信息对象txt
document.getElementById( "msgDiv").appendChild(button);//在提示框div中添加按钮对象button
}
</script>
注意style.position和style.zIndex两属性。
