jsbin.kofuj.css

.container{
  width:95%;
  height:200px;
  background: #f90;
  margin: 10px auto 0;
  position: relative;
}

.box-1{
  width:30%;
  /* height:30%; */
  height:auto;
  background: green;
  position: absolute;
  text-align:center;
}

.box-2{
  width:30%;
  /* height:30%; */
  height:auto;
  background: green;
  position: absolute;
  text-align:center;
}
 

jsbin.kofuj.html

<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script><meta name="description" content="js方法绝定定位元素居中" />

<div class="container">
    <div class="box-1">
      Lorem ipsum dolor sit amet
      dolor sit amet
    </div>
 </div>

<div class="container">
    <div class="box-2">
      Lorem ipsum dolor sit amet
      dolor sit amet
    </div>
 </div>

jsbin.kofuj.js

/**
 * @author: Suissa
 * @name: Absolute Center
 * @date: 2007-10-09
 */

/*这个插件是相对于windows窗口的*/
jQuery.fn.center = function() {
	return this.each(function(){
			var el = $(this);
			var h = el.height();
			var w = el.width();
			var w_box = $(window).width();
			var h_box = $(window).height();	
			var w_total = (w_box - w)/2; //400
			var h_total = (h_box - h)/2;
			var css = {"position": 'absolute', "left": w_total+"px", "top":
h_total+"px"};
			el.css(css);
	});
};

$(function(){
  $('.box-1').click(function(){
    alert(123);
  });

  $('.box-1').center();

  $(window).resize(function(){
      $('.box-1').center();
  });
});

/*相对于父元素居中对齐*/
jQuery.fn.centerParent = function(parent) {
	return this.each(function(){
			var el = $(this);
			var h = el.height();
			var w = el.width();
			var w_box = parent.width();
			var h_box = parent.height();	
			var w_total = (w_box - w)/2; //400
			var h_total = (h_box - h)/2;
			var css = {"position": 'absolute', "left": w_total+"px", "top":
h_total+"px"};
			el.css(css);
	});
};

$(function(){
  var parent = $('.container');
  $('.box-2').centerParent(parent);

  $(window).resize(function(){
      $('.box-2').centerParent(parent);
  });
});