如何让JS弹出的层绝对屏幕居中
<!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=utf-8" /><title>无标题文档</title><style type="text/css">/*弹出层的STYLE*/html,body {height:100%; margin:0px; font-size:12px;}.mydiv {background-color: #ff6;border: 1px solid #f90;text-align: center;line-height: 40px;font-size: 12px;font-weight: bold;z-index:99;width: 300px;height: 120px;left:50%;/*FF IE7*/top: 50%;/*FF IE7*/margin-left:-150px!important;/*FF IE7 该值为本身宽的一半 */margin-top:-60px!important;/*FF IE7 该值为本身高的一半*/margin-top:0px;position:fixed!important;/*FF IE7*/position:absolute;/*IE6*/_top: expression(eval(document.compatMode && document.compatMode=='CSS1Compat') ? documentElement.scrollTop + (document.documentElement.clientHeight-this.offsetHeight)/2 :/*IE6*/ document.body.scrollTop + (document.body.clientHeight - this.clientHeight)/2);/*IE5 IE5.5*/}.bg {background-color: #ccc;width: 100%;height: 100%;left:0;top:0;/*FF IE7*/filter:alpha(opacity=50);/*IE*/opacity:0.5;/*FF*/z-index:1;position:fixed!important;/*FF IE7*/position:absolute;/*IE6*/_top: expression(eval(document.compatMode && document.compatMode=='CSS1Compat') ? documentElement.scrollTop + (document.documentElement.clientHeight-this.offsetHeight)/2 :/*IE6*/ document.body.scrollTop + (document.body.clientHeight - this.clientHeight)/2);/*IE5 IE5.5*/}/*The END*/</style><script type="text/javascript">function showDiv(){document.getElementById('popDiv').style.display='block';document.getElementById('bg').style.display='block';}function closeDiv(){document.getElementById('popDiv').style.display='none';document.getElementById('bg').style.display='none';}</script></head><body><div id="popDiv" style="display:none;">恭喜你！<br/>你的成绩为:60分<br/><a href="javascript:closeDiv()">关闭窗口</a></div><div id="bg" style="display:none;"></div><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><div style="padding-top: 20px;"><input type="Submit" name="" value="显示层" onclick="javascript:showDiv()" /></div></body></html>?
第二种
<!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>JavaScript 仿LightBox内容显示效果</title> </head> <body> <script> var isIE = (document.all) ? true : false; var isIE6 = isIE && ([/MSIE (\d)\.0/i.exec(navigator.userAgent)][0][1] == 6); var $ = function (id) { return "string" == typeof id ? document.getElementById(id) : id; }; var Class = { create: function() { return function() { this.initialize.apply(this, arguments); } } } var Extend = function(destination, source) { for (var property in source) { destination[property] = source[property]; } } var Bind = function(object, fun) { return function() { return fun.apply(object, arguments); } } var Each = function(list, fun){ for (var i = 0, len = list.length; i < len; i++) { fun(list[i], i); } }; var Contains = function(a, b){ return a.contains ? a != b && a.contains(b) : !!(a.compareDocumentPosition(b) & 16); } var OverLay = Class.create(); OverLay.prototype = { initialize: function(options) { this.SetOptions(options); this.Lay = $(this.options.Lay) || document.body.insertBefore(document.createElement("div"), document.body.childNodes[0]); this.Color = this.options.Color; this.Opacity = parseInt(this.options.Opacity); this.zIndex = parseInt(this.options.zIndex); with(this.Lay.style){ display = "none"; zIndex = this.zIndex; left = top = 0; position = "fixed"; width = height = "100%"; } if(isIE6){ this.Lay.style.position = "absolute"; //ie6设置覆盖层大小程序 this._resize = Bind(this, function(){ this.Lay.style.width = Math.max(document.documentElement.scrollWidth, document.documentElement.clientWidth) + "px"; this.Lay.style.height = Math.max(document.documentElement.scrollHeight, document.documentElement.clientHeight) + "px"; }); //遮盖select this.Lay.innerHTML = '<iframe style="position:absolute;top:0;left:0;width:100%;height:100%;filter:alpha(opacity=0);"></iframe>' } }, //设置默认属性 SetOptions: function(options) { this.options = {//默认值 Lay: null,//覆盖层对象 Color: "#fff",//背景色 Opacity: 50,//透明度(0-100) zIndex: 1000//层叠顺序 }; Extend(this.options, options || {}); }, //显示 Show: function() { //兼容ie6 if(isIE6){ this._resize(); window.attachEvent("onresize", this._resize); } //设置样式 with(this.Lay.style){ //设置透明度 isIE ? filter = "alpha(opacity:" + this.Opacity + ")" : opacity = this.Opacity / 100; backgroundColor = this.Color; display = "block"; } }, //关闭 Close: function() { this.Lay.style.display = "none"; if(isIE6){ window.detachEvent("onresize", this._resize); } } }; var LightBox = Class.create(); LightBox.prototype = { initialize: function(box, options) { this.Box = $(box);//显示层 this.OverLay = new OverLay(options);//覆盖层 this.SetOptions(options); this.Fixed = !!this.options.Fixed; this.Over = !!this.options.Over; this.Center = !!this.options.Center; this.onShow = this.options.onShow; this.Box.style.zIndex = this.OverLay.zIndex + 1; this.Box.style.display = "none"; //兼容ie6用的属性 if(isIE6){ this._top = this._left = 0; this._select = []; this._fixed = Bind(this, function(){ this.Center ? this.SetCenter() : this.SetFixed(); }); } }, //设置默认属性 SetOptions: function(options) { this.options = {//默认值 Over: true,//是否显示覆盖层 Fixed: false,//是否固定定位 Center: false,//是否居中 onShow: function(){}//显示时执行 }; Extend(this.options, options || {}); }, //兼容ie6的固定定位程序 SetFixed: function(){ this.Box.style.top = document.documentElement.scrollTop - this._top + this.Box.offsetTop + "px"; this.Box.style.left = document.documentElement.scrollLeft - this._left + this.Box.offsetLeft + "px"; this._top = document.documentElement.scrollTop; this._left = document.documentElement.scrollLeft; }, //兼容ie6的居中定位程序 SetCenter: function(){ this.Box.style.marginTop = document.documentElement.scrollTop - this.Box.offsetHeight / 2 + "px"; this.Box.style.marginLeft = document.documentElement.scrollLeft - this.Box.offsetWidth / 2 + "px"; }, //显示 Show: function(options) { //固定定位 this.Box.style.position = this.Fixed && !isIE6 ? "fixed" : "absolute"; //覆盖层 this.Over && this.OverLay.Show(); this.Box.style.display = "block"; //居中 if(this.Center){ this.Box.style.top = this.Box.style.left = "50%"; //设置margin if(this.Fixed){ this.Box.style.marginTop = - this.Box.offsetHeight / 2 + "px"; this.Box.style.marginLeft = - this.Box.offsetWidth / 2 + "px"; }else{ this.SetCenter(); } } //兼容ie6 if(isIE6){ if(!this.Over){ //没有覆盖层ie6需要把不在Box上的select隐藏 this._select.length = 0; Each(document.getElementsByTagName("select"), Bind(this, function(o){ if(!Contains(this.Box, o)){ o.style.visibility = "hidden"; this._select.push(o); } })) } //设置显示位置 this.Center ? this.SetCenter() : this.Fixed && this.SetFixed(); //设置定位 this.Fixed && window.attachEvent("onscroll", this._fixed); } this.onShow(); }, //关闭 Close: function() { this.Box.style.display = "none"; this.OverLay.Close(); if(isIE6){ window.detachEvent("onscroll", this._fixed); Each(this._select, function(o){ o.style.visibility = "visible"; }); } } }; </script> <style> .lightbox{width:300px;background:#FFFFFF;border:1px solid #ccc;line-height:25px; top:20%; left:20%;} .lightbox dt{background:#f4f4f4; padding:5px;} </style> <dl id="idBox" type="button" value=" 关闭 " id="idBoxCancel" /> <br /><br /> </dd> </dl> <div style="margin:0 auto; width:800px; height:500px; border:1px solid #000000;"> <input type="button" value="关闭覆盖层" id="btnOverlay" /> <input type="button" value="黑色覆盖层" id="btnOverColor" /> <input type="button" value="全透覆盖层" id="btnOverOpacity" /> <input type="button" value="定位效果" id="btnFixed" /> <input type="button" value="居中效果" id="btnCenter" /> <br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /> <select> <option>覆盖select测试</option> </select> <input name="" type="button" value=" 打开 " id="idBoxOpen" /> </div> <script> var box = new LightBox("idBox"); $("idBoxCancel").onclick = function(){ box.Close(); } $("idBoxOpen").onclick = function(){ box.Show(); } $("btnOverlay").onclick = function(){ box.Close(); if(box.Over){ box.Over = false; this.value = "打开覆盖层"; } else { box.Over = true; this.value = "关闭覆盖层"; } } $("btnOverColor").onclick = function(){ box.Close(); box.Over = true; if(box.OverLay.Color == "#fff"){ box.OverLay.Color = "#000"; this.value = "白色覆盖层"; } else { box.OverLay.Color = "#fff" this.value = "黑色覆盖层"; } } $("btnOverOpacity").onclick = function(){ box.Close(); box.Over = true; if(box.OverLay.Opacity == 0){ box.OverLay.Opacity = 50; this.value = "全透覆盖层"; } else { box.OverLay.Opacity = 0; this.value = "半透覆盖层"; } } $("btnFixed").onclick = function(){ box.Close(); if(box.Fixed){ box.Fixed = false; this.value = "定位效果"; } else { box.Fixed = true; this.value = "取消定位"; } } $("btnCenter").onclick = function(){ box.Close(); if(box.Center){ box.Center = false; box.Box.style.left = box.Box.style.top = "20%"; box.Box.style.marginTop = box.Box.style.marginLeft = "0"; this.value = "居中效果"; } else { box.Center = true; this.value = "重新定位"; } } </script> </body> </html>?