我会使用translate:

首先，将div的左上角定位在页面的中心(使用位置:固定;上图:50%;左:50%)。然后，translate将其向上移动50%的div高度，使其在页面上垂直居中。最后，translate还将div向右移动50%的宽度，使其水平居中。

实际上，我认为这个方法比其他许多方法更好，因为它不需要对父元素进行任何更改。

在某些情况下，Translate比translate3d更好，因为它被更多的浏览器支持。https://caniuse.com/#feat=transforms2d

综上所述，所有版本的Chrome、Firefox 3.5+、Opera 11.5+、所有版本的Safari、IE 9+和Edge都支持此方法。

.centered { position: fixed; top: 50%; left: 50%; transform: translate(-50%, -50%); -webkit-transform: translate(-50%, -50%); -moz-transform: translate(-50%, -50%); -o-transform: translate(-50%, -50%); -ms-transform: translate(-50%, -50%); font-size: 20px; background-color: cyan; border: darkgreen 5px solid; padding: 5px; z-index: 100; } table { position: absolute; top: 0; left: 0; } td { position: relative; top: 0; left: 0; } <table> <tr> <td> <div class="centered">This div<br />is centered</div> <p> Lorem ipsum dolor sit amet, nam sint laoreet at, his ne sumo causae, simul decore deterruisset ne mel. Exerci atomorum est ut. At choro vituperatoribus usu. Dico epicurei persequeris quo ex, ea ius zril phaedrum eloquentiam, duo in aperiam admodum fuisset. No quidam consequuntur usu, in amet hinc simul eos. Ex soleat meliore percipitur mea, nihil omittam salutandi ut eos. Mea et impedit facilisi pertinax, ea viris graeci fierent pri, te sonet intellegebat his. Vis denique albucius instructior ad, ex eum iudicabit elaboraret. Sit ea intellegam liberavisse. Nusquam quaestio maiestatis ut qui, eam decore altera te. Unum cibo aliquip ut qui, te mea doming prompta. Ex rebum interesset nam, te nam zril suscipit, qui suavitate explicari appellantur te. Usu brute corpora mandamus eu. Dicit soluta his eu. In sint consequat sed, quo ea tota petentium. Adhuc prompta splendide mel ad, soluta delenit nec cu. </p> </td> <td> <p> Lorem ipsum dolor sit amet, dico choro recteque te cum, ex omnesque consectetuer sed, alii esse utinam et has. An qualisque democritum usu. Ea has habeo labores, laoreet intellegat te mea. Eius equidem inermis vel ne. Ne eum sonet labitur, nec id natum munere. Primis graecis est cu, quis dictas eu mea, eu quem offendit forensibus nec. Id animal mandamus his, vis in sonet tempor luptatum. Ne civibus oporteat comprehensam vix, per facete discere atomorum eu. Mucius probatus volutpat sit an, sumo nominavi democritum eam ut. Ea sit choro graece debitis, per ex verear voluptua epicurei. Id eum wisi dicat, ea sit velit doming cotidieque, eu sea amet delenit. Populo tacimates dissentiunt has cu. Has wisi hendrerit at, et quo doming putent docendi. Ea nibh vide omnium usu. </p> </td> </tr> </table>

但是，请注意，该方法使该div在页面滚动时停留在一个位置。这可能是你想要的，但如果不是，还有另一种方法。

现在，如果我们尝试相同的CSS，但将位置设置为绝对，它将在最后一个具有绝对位置的父元素的中心。

.centered { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); -webkit-transform: translate(-50%, -50%); -moz-transform: translate(-50%, -50%); -o-transform: translate(-50%, -50%); -ms-transform: translate(-50%, -50%); font-size: 20px; background-color: cyan; border: darkgreen 5px solid; padding: 5px; z-index: 100; } table { position: absolute; top: 0; left: 0; } td { position: relative; top: 0; left: 0; } <table> <tr> <td> <div class="centered">This div<br />is centered</div> <p> Lorem ipsum dolor sit amet, nam sint laoreet at, his ne sumo causae, simul decore deterruisset ne mel. Exerci atomorum est ut. At choro vituperatoribus usu. Dico epicurei persequeris quo ex, ea ius zril phaedrum eloquentiam, duo in aperiam admodum fuisset. No quidam consequuntur usu, in amet hinc simul eos. Ex soleat meliore percipitur mea, nihil omittam salutandi ut eos. Mea et impedit facilisi pertinax, ea viris graeci fierent pri, te sonet intellegebat his. Vis denique albucius instructior ad, ex eum iudicabit elaboraret. Sit ea intellegam liberavisse. Nusquam quaestio maiestatis ut qui, eam decore altera te. Unum cibo aliquip ut qui, te mea doming prompta. Ex rebum interesset nam, te nam zril suscipit, qui suavitate explicari appellantur te. Usu brute corpora mandamus eu. Dicit soluta his eu. In sint consequat sed, quo ea tota petentium. Adhuc prompta splendide mel ad, soluta delenit nec cu. </p> </td> <td> <p> Lorem ipsum dolor sit amet, dico choro recteque te cum, ex omnesque consectetuer sed, alii esse utinam et has. An qualisque democritum usu. Ea has habeo labores, laoreet intellegat te mea. Eius equidem inermis vel ne. Ne eum sonet labitur, nec id natum munere. Primis graecis est cu, quis dictas eu mea, eu quem offendit forensibus nec. Id animal mandamus his, vis in sonet tempor luptatum. Ne civibus oporteat comprehensam vix, per facete discere atomorum eu. Mucius probatus volutpat sit an, sumo nominavi democritum eam ut. Ea sit choro graece debitis, per ex verear voluptua epicurei. Id eum wisi dicat, ea sit velit doming cotidieque, eu sea amet delenit. Populo tacimates dissentiunt has cu. Has wisi hendrerit at, et quo doming putent docendi. Ea nibh vide omnium usu. </p> </td> </tr> </table>

下面是我之前写的一个脚本(它是用jQuery库写的):

var centerIt = function (el /* (jQuery element) Element to center */) {
    if (!el) {
        return;
    }
    var moveIt = function () {
        var winWidth = $(window).width();
        var winHeight = $(window).height();
        el.css("position","absolute").css("left", ((winWidth / 2) - (el.width() / 2)) + "px").css("top", ((winHeight / 2) - (el.height() / 2)) + "px");
    }; 
    $(window).resize(moveIt);
    moveIt();
};

我会使用translate:

首先，将div的左上角定位在页面的中心(使用位置:固定;上图:50%;左:50%)。然后，translate将其向上移动50%的div高度，使其在页面上垂直居中。最后，translate还将div向右移动50%的宽度，使其水平居中。

实际上，我认为这个方法比其他许多方法更好，因为它不需要对父元素进行任何更改。

在某些情况下，Translate比translate3d更好，因为它被更多的浏览器支持。https://caniuse.com/#feat=transforms2d

综上所述，所有版本的Chrome、Firefox 3.5+、Opera 11.5+、所有版本的Safari、IE 9+和Edge都支持此方法。

.centered { position: fixed; top: 50%; left: 50%; transform: translate(-50%, -50%); -webkit-transform: translate(-50%, -50%); -moz-transform: translate(-50%, -50%); -o-transform: translate(-50%, -50%); -ms-transform: translate(-50%, -50%); font-size: 20px; background-color: cyan; border: darkgreen 5px solid; padding: 5px; z-index: 100; } table { position: absolute; top: 0; left: 0; } td { position: relative; top: 0; left: 0; } <table> <tr> <td> <div class="centered">This div<br />is centered</div> <p> Lorem ipsum dolor sit amet, nam sint laoreet at, his ne sumo causae, simul decore deterruisset ne mel. Exerci atomorum est ut. At choro vituperatoribus usu. Dico epicurei persequeris quo ex, ea ius zril phaedrum eloquentiam, duo in aperiam admodum fuisset. No quidam consequuntur usu, in amet hinc simul eos. Ex soleat meliore percipitur mea, nihil omittam salutandi ut eos. Mea et impedit facilisi pertinax, ea viris graeci fierent pri, te sonet intellegebat his. Vis denique albucius instructior ad, ex eum iudicabit elaboraret. Sit ea intellegam liberavisse. Nusquam quaestio maiestatis ut qui, eam decore altera te. Unum cibo aliquip ut qui, te mea doming prompta. Ex rebum interesset nam, te nam zril suscipit, qui suavitate explicari appellantur te. Usu brute corpora mandamus eu. Dicit soluta his eu. In sint consequat sed, quo ea tota petentium. Adhuc prompta splendide mel ad, soluta delenit nec cu. </p> </td> <td> <p> Lorem ipsum dolor sit amet, dico choro recteque te cum, ex omnesque consectetuer sed, alii esse utinam et has. An qualisque democritum usu. Ea has habeo labores, laoreet intellegat te mea. Eius equidem inermis vel ne. Ne eum sonet labitur, nec id natum munere. Primis graecis est cu, quis dictas eu mea, eu quem offendit forensibus nec. Id animal mandamus his, vis in sonet tempor luptatum. Ne civibus oporteat comprehensam vix, per facete discere atomorum eu. Mucius probatus volutpat sit an, sumo nominavi democritum eam ut. Ea sit choro graece debitis, per ex verear voluptua epicurei. Id eum wisi dicat, ea sit velit doming cotidieque, eu sea amet delenit. Populo tacimates dissentiunt has cu. Has wisi hendrerit at, et quo doming putent docendi. Ea nibh vide omnium usu. </p> </td> </tr> </table>

但是，请注意，该方法使该div在页面滚动时停留在一个位置。这可能是你想要的，但如果不是，还有另一种方法。

现在，如果我们尝试相同的CSS，但将位置设置为绝对，它将在最后一个具有绝对位置的父元素的中心。

.centered { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); -webkit-transform: translate(-50%, -50%); -moz-transform: translate(-50%, -50%); -o-transform: translate(-50%, -50%); -ms-transform: translate(-50%, -50%); font-size: 20px; background-color: cyan; border: darkgreen 5px solid; padding: 5px; z-index: 100; } table { position: absolute; top: 0; left: 0; } td { position: relative; top: 0; left: 0; } <table> <tr> <td> <div class="centered">This div<br />is centered</div> <p> Lorem ipsum dolor sit amet, nam sint laoreet at, his ne sumo causae, simul decore deterruisset ne mel. Exerci atomorum est ut. At choro vituperatoribus usu. Dico epicurei persequeris quo ex, ea ius zril phaedrum eloquentiam, duo in aperiam admodum fuisset. No quidam consequuntur usu, in amet hinc simul eos. Ex soleat meliore percipitur mea, nihil omittam salutandi ut eos. Mea et impedit facilisi pertinax, ea viris graeci fierent pri, te sonet intellegebat his. Vis denique albucius instructior ad, ex eum iudicabit elaboraret. Sit ea intellegam liberavisse. Nusquam quaestio maiestatis ut qui, eam decore altera te. Unum cibo aliquip ut qui, te mea doming prompta. Ex rebum interesset nam, te nam zril suscipit, qui suavitate explicari appellantur te. Usu brute corpora mandamus eu. Dicit soluta his eu. In sint consequat sed, quo ea tota petentium. Adhuc prompta splendide mel ad, soluta delenit nec cu. </p> </td> <td> <p> Lorem ipsum dolor sit amet, dico choro recteque te cum, ex omnesque consectetuer sed, alii esse utinam et has. An qualisque democritum usu. Ea has habeo labores, laoreet intellegat te mea. Eius equidem inermis vel ne. Ne eum sonet labitur, nec id natum munere. Primis graecis est cu, quis dictas eu mea, eu quem offendit forensibus nec. Id animal mandamus his, vis in sonet tempor luptatum. Ne civibus oporteat comprehensam vix, per facete discere atomorum eu. Mucius probatus volutpat sit an, sumo nominavi democritum eam ut. Ea sit choro graece debitis, per ex verear voluptua epicurei. Id eum wisi dicat, ea sit velit doming cotidieque, eu sea amet delenit. Populo tacimates dissentiunt has cu. Has wisi hendrerit at, et quo doming putent docendi. Ea nibh vide omnium usu. </p> </td> </tr> </table>

虽然我太晚了，但这很简单。页面中心总是向左50%，顶部50%。减去div width和height的50%设置左右边距。希望它适用于所有地方

身体{ 背景:# EEE; ｝ .center-div { 位置:绝对的; 宽度:200 px; 高度:60 px; 左:50%; margin-left: -100 px; 上图:50%; margin-top: -30 px; 背景:# CCC; 颜色:# 000; text-align:中心; ｝ < div class = " center-div”> <h3>这是中心div</h3> < / div >

我喜欢的方法是将一个盒子垂直和水平居中，是以下技术:

外容器

应有显示:表;

内容器

应该有display: table-cell; 应该有垂直对齐:中间; 应该有text-align: center;

内容框

应该有显示:inline-block; 应该重新调整水平文本对齐，如。text-align:左;或者text-align: right;，除非你想让文本居中

这种技术的优雅之处在于，你可以将你的内容添加到内容框中，而不用担心它的高度或宽度!

Demo

body { margin : 0; } .outer-container { position : absolute; display: table; width: 100%; /* This could be ANY width */ height: 100%; /* This could be ANY height */ background: #ccc; } .inner-container { display: table-cell; vertical-align: middle; text-align: center; } .centered-content { display: inline-block; text-align: left; background: #fff; padding : 20px; border : 1px solid #000; } <div class="outer-container"> <div class="inner-container"> <div class="centered-content"> You can put anything here! </div> </div> </div>

看看这小提琴!

EDIT

是的，我知道你可以通过transform实现或多或少相同的灵活性:translate(-50%， -50%);或者transform: translate3d(-50%，-50%， 0);，我建议的技术有更好的浏览器支持。即使使用浏览器前缀，如-webkit， -ms或-moz, transform也不能提供完全相同的浏览器支持。

所以如果你关心旧的浏览器(例如。IE9及以下版本)，您不应该使用transform进行定位。

这个解决方案对我很有效

    .middleDiv{
        position : absolute;
        height : 90%;
        bottom: 5%;
    }

(或高度:70% /底部:15%

高度:40% /底部:30%…)