javascript实现点击按钮弹出一个可关闭层窗口同时网页背景变灰的方法

更新时间：2026-08-08 15:16:26作者：zhao

本文实例讲述了javascript实现点击按钮弹出一个可关闭层窗口同时网页背景变灰的方法。分享给大家供大家参考。具体分析如下：

这里点击按钮后，弹出一个可关闭的层窗口，随之网页背景变灰，在QQ网站上经常会看到QQ登录的效果，就和这个很类似，代码段基于JavaScript，根据你的情况使用，有时候是用CSS完成的这种功能。

<html>

<head>

<title>弹出一个层，页面变灰</title>

function alertWin(title, msg, w, h){

var titleheight = "23px"; // 窗口标题高度

var bordercolor = "#336699"; // 提示窗口的边框颜色

var titlecolor = "#FFFFFF"; // 窗口标题颜色

var titlebgcolor = "#336699"; // 窗口标题背景色

var bgcolor = "#FFFFFF"; // 提示内容的背景色

var iWidth = document.documentElement.clientWidth;

var iHeight = document.documentElement.clientHeight;

var bgObj = document.createElement("div");

bgObj.style.cssText = "position:absolute;left:0px;top:0px;width:"+iWidth+"px;height:"+Math.max(document.body.clientHeight, iHeight)+"px;filter:Alpha(Opacity=30);opacity:0.3;background-color:#000000;z-index:101;";

document.body.appendChild(bgObj);

var msgObj=document.createElement("div");

msgObj.style.cssText = "position:absolute;font:11px '宋体';top:"+(iHeight-h)/2+"px;left:"+(iWidth-w)/2+"px;width:"+w+"px;height:"+h+"px;text-align:center;border:1px solid "+bordercolor+";background-color:"+bgcolor+";padding:1px;line-height:22px;z-index:102;";

document.body.appendChild(msgObj);

var table = document.createElement("table");

msgObj.appendChild(table);

table.style.cssText = "margin:0px;border:0px;padding:0px;";

table.cellSpacing = 0;

var tr = table.insertRow(-1);

var titleBar = tr.insertCell(-1);

titleBar.style.cssText = "width:100%;height:"+titleheight+"px;text-align:left;padding:3px;margin:0px;font:bold 13px '宋体';color:"+titlecolor+";border:1px solid " + bordercolor + ";cursor:move;background-color:" + titlebgcolor;

titleBar.style.paddingLeft = "10px";

titleBar.innerHTML = title;

var moveX = 0;

var moveY = 0;

var moveTop = 0;

var moveLeft = 0;

var moveable = false;

var docMouseMoveEvent = document.onmousemove;

var docMouseUpEvent = document.onmouseup;

titleBar.onmousedown = function() {

var evt = getEvent();

moveable = true;

moveX = evt.clientX;

moveY = evt.clientY;

moveTop = parseInt(msgObj.style.top);

moveLeft = parseInt(msgObj.style.left);

document.onmousemove = function() {

if (moveable) {

var evt = getEvent();

var x = moveLeft + evt.clientX - moveX;

var y = moveTop + evt.clientY - moveY;

if ( x > 0 &&( x + w < iWidth) && y > 0 && (y + h < iHeight) ) {

msgObj.style.left = x + "px";

msgObj.style.top = y + "px";

}

};

document.onmouseup = function () {

if (moveable) {

document.onmousemove = docMouseMoveEvent;

document.onmouseup = docMouseUpEvent;

moveable = false;

moveX = 0;

moveY = 0;

moveTop = 0;

moveLeft = 0;

}

};

}

var closeBtn = tr.insertCell(-1);

closeBtn.style.cssText = "cursor:pointer; padding:2px;background-color:" + titlebgcolor;

closeBtn.innerHTML = "<span style='font-size:15pt; color:"+titlecolor+";'>×</span>";

closeBtn.onclick = function(){

document.body.removeChild(bgObj);

document.body.removeChild(msgObj);

}

var msgBox = table.insertRow(-1).insertCell(-1);

msgBox.style.cssText = "font:10pt '宋体';";

msgBox.colSpan = 2;

msgBox.innerHTML = msg;

// 获得Event对象，用于兼容IE和FireFox

function getEvent() {

return window.event || arguments.callee.caller.arguments[0];

}

</script>

</head>

<body>

<input type="button" value="点这里"

onclick="alertWin('点击弹出可关闭的层窗口，网页变灰',290,208);" />

</body>

</html>

希望本文所述对大家的javascript程序设计有所帮助。