我已经尝试过table-cell方法,但无法让它工作.我听说这是由于绝对的定位并尝试了这个解决方案没有运气：
CSS – Vertical align table-cell don’t work with position absolute

这似乎是由于.table-cell没有高度 – 我希望它的高度等于其父容器,其高度不同.

的jsfiddle：

http://jsfiddle.net/q5jKM/1/

有没有人知道如何让绿色div.middle元素垂直对齐到中间？任何方法都可以.它只需要能够处理其可变高度.只用css有可能吗？或者我是否必须加入一些jQuery？

编辑：

Box-align也不是一个可行的解决方案,因为浏览器支持并被新标准取代.

CSS

html,body{height:100%;margin:0}
#sidebar {
    width: 22em;
    position:fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index:2;
    color: #ffffff;
    background-color: #333333;  
    overflow:auto;
    height: 100%;
}

#sidebar .nav {
    width: 3em;
    float: right;
    background-color: #2e2e2e;
    border-left: 2px groove #454545;
    height: 100%;
    position:relative;
    min-height:34em;    
}

#sidebar .content {
    height: 100%; 
    width: 16.875em; /*    17-(2/16)   - 20em - .nav - nav border*/
    float:left; 
    position:relative;
    min-height:34em;
}

#sidebar .top {
    position:absolute;
    top:0;
}
#sidebar .bottom {
    position:absolute;
    bottom:0;
}

#sidebar .middle {
    position: absolute;
    bottom: 12em;       /*  3.125*3  */
    top: 16em;          /*  3.125*4  */
    background: green;
}

.content .middle {
    overflow:auto;
}


#sidebar .content > div {width: 16.875em; } /*.top .middle .bottom*/
#sidebar .nav > div {width:3em; } /*.top .middle .bottom*/


    /*table-cell trying get vertical-align working*/
#sidebar .table-cell {display:table-cell; vertical-align: middle; }



#sidebar .content p,#sidebar .content li,#sidebar .content img {font-size: .75em; color: #dddddd;}

#sidebar ul {margin:0; padding: 0;}









#sidebar .nav li {
    padding: .5625em;
    list-style:none;
}
#sidebar .nav li img {
    height: 1.875em;
    width: 1.875em
}

#sidebar .nav .top li { border-bottom: 2px groove #454545 }
#sidebar .nav .bottom li { border-top:  2px groove #454545 }




.content li {
    position:relative;
    display:block;
    background-color: #444;
    padding: .72em;
    border-radius: .8em;
    border-bottom: 1px solid #292929;
    border-top: 1px solid #4c4c4c;
    text-align: center;
    font-size: 1em;
    letter-spacing: .1em;
    font-weight: normal;
    height: 1.2em;
}

.content li:after {
    content:"";
    position:absolute;
    display:block; 
    width:0;
    top:.11em; /* controls vertical position */
    right:-.852em; /* value = - border-left-width - border-right-width */
    border-style:solid;
    border-width:1.2em 0 1.2em 1.2em;
    border-color:transparent #444;
}

.content .top li{margin: .95em 0 1.9em 0;}
.content .bottom li{margin: 1.9em 0 .95em 0;}

.content .logo {
    text-align: center;
    padding: 1em 0 2em 0;
    width: 100%;
    border-bottom: 2px groove #454545;
}
.content p.welcome {
    text-align: center;
    line-height: 1.5em;
    margin: 1em 0;
}

HTML

<div id="sidebar">


            <div class="nav">
            <div class="top">
            <ul>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
            </ul>
            </div>
            <div class="middle"><div class="table-cell"><p>test</p></div></div>
            <div class="bottom">
            <ul>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
            </ul>
            </div>
            </div>



            <div class="content">
                <div class="top">
                <ul>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                </ul>
                </div>
                <div class="middle"><div class="table-cell">
                <div class="logo"><img src="_images/g.svg"></div>
                <p class="welcome">Lorem ipsum dolor sit amet,consectetur adipiscing elit. Mauris dictum tellus viverra neque bibendum in mattis ante dignissim. Nam mattis feugiat lorem porttitor adipiscing. Aliquam erat volutpat. Nunc feugiat magna vitae mauris egestas euismod. In hac habitasse platea dictumst. Praesent magna sem,malesuada non fermentum vel,luctus quis mauris. Duis quam purus,ornare vitae eleifend sed,malesuada eget libero. Phasellus sed lorem risus,nec placerat urna. In magna turpis,accumsan ac egestas quis,dictum vel massa. Nulla vitae magna arcu. Maecenas sit amet vestibulum urna. Integer feugiat dignissim leo sed ornare. Maecenas auctor ultricies dui,pulvinar tincidunt velit feugiat quis. Sed egestas ornare elit,et fringilla quam viverra ut.</p>
                </div></div>
                <div class="bottom">
                <ul>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                </ul>
                </div>
                </div>
    </div>