是浏览器支持的，使用翻译功能强大。

position: absolute;
background-color: red;

width: 70%;     
height: 30%; 

/* The translate % is relative to the size of the div and not the container*/ 
/* 21.42% = ( (100%-70%/2) / 0.7 ) */
/* 116.666% = ( (100%-30%/2) / 0.3 ) */
transform: translate3d( 21.42%, 116.666%, 0);

解决方案

仅使用两行CSS，利用Flexbox的神奇力量

.parent { display: flex; }
.child { margin: auto }

请使用以下CSS属性水平和垂直居中对齐元素。这对我来说很有效。

div {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0px;
  margin: auto;
  width: 100px;
  height: 100px;
}

这项技术的简单性令人惊叹: (尽管这个方法有它的含义，但是如果您只需要将元素居中，而不考虑其余内容的流，那么它是可以的。小心使用)

标记:

<div>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum accumsan tellus purus, et mollis nulla consectetur ac. Quisque id elit at diam convallis venenatis eget sed justo. Nunc egestas enim mauris, sit amet tempor risus ultricies in. Sed dignissim magna erat, vel laoreet tortor bibendum vitae. Ut porttitor tincidunt est imperdiet vestibulum. Vivamus id nibh tellus. Integer massa orci, gravida non imperdiet sed, consectetur ac quam. Nunc dignissim felis id tortor tincidunt, a eleifend nulla molestie. Phasellus eleifend leo purus, vel facilisis massa dignissim vitae. Pellentesque libero sapien, tincidunt ut lorem non, porta accumsan risus. Morbi tempus pharetra ex, vel luctus turpis tempus eu. Integer vitae sagittis massa, id gravida erat. Maecenas sed purus et magna tincidunt faucibus nec eget erat. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nunc nec mollis sem.</div>

和CSS:

div {
  color: white;
  background: red;
  padding: 15px;
  position: absolute;
  top: 50%;
  left: 50%;
  -ms-transform: translateX(-50%) translateY(-50%);
  -webkit-transform: translate(-50%,-50%);
  transform: translate(-50%,-50%);
}   

这将使元素水平和垂直居中。没有负边距，只有变换的幂。我们也应该忘记IE8，不是吗?

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%…)

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();
};