绝对中心流体div

再会。

我知道如果你想将 div 绝对居中，你可以这样做：

<div id="parent">
   <div id="child">blahblah</div>
</div>

CSS:

#parent{
   width: 500px;
   height: 500px;
   position: absolute; /*(or relative)*/
   top: 50%;
   left: 50%;
   margin-top: -250px;
   margin-left: -250px;
   text-align: center;
}

如果父div是流体div怎么办？你如何绝对居中它的意思：

#parent{
  max-width: 500px;
  max-height: 500px;
  top: 50%; ->is this right?
  left: 50%; -> is this right?
  margin-top: ???;
  margin-left: ???;
  text-align: center;
}

As the width and height是流畅的，你需要使用 javascript 或 jQuery。只需添加以下代码即可head tag. (下面的例子是在javascript中)

<script>
   window.onresize = function(){
      //To work even on resize
      getToMiddle();
   }
   window.onload = function(){
      getToMiddle();
   }

   function getToMiddle(){
      var box = document.getElementById('parent');
      var height = box.offsetHeight;
      var width = box.offsetWidth;
      box.style.top = -(height/2);
      box.style.left = -(width/2);
   }
</script>

你的CSS将是这样的：

#parent{
   max-width: 500px;
   max-height: 500px;
   background-color:green;
   position:absolute;
   top: 50%;
   left: 50%;
  /* width: 10%;
   height: 10%; */
}

为了测试，给width: 10%; and height: 10%

工作小提琴 http://jsbin.com/ewizad/7/edit