Center two containers with absolute position within a div - css

Question

Using CSS, I want to horizontally center two "boxes" I have within a div. The boxes are absolutely positioned.
Here is the JSFiddle: http://jsfiddle.net/p4sA3/8/
How would I achieve this without using specific widths?
HTML:
<button id="change">Change</button>
<div id="total-wrap">
<div id="hello-wrap" class="bunch">
<div id="box">
<p> Hello, this is text1 </p>
</div>
<div id="box">
<p> Hello, this is text2 </p>
</div>
</div>
<div id="goodbye-wrap" class="bunch">
<div id="box">
<p> Goodbye, this is text1 </p>
</div>
<div id="box">
<p> Goodbye, this is text2 </p>
</div>
</div>
</div>
CSS:
#total-wrap {
border:1px solid #000;
height:500px;
}
#box {
position:relative;
display:inline-block;
width:300px;
height:100px;
background-color:yellow;
margin:10px;
}
.bunch {
position: absolute;
text-align:center;
}

Answer 1

I would do it with left:0; and right:0 as they are absolutely positioned.
DEMO http://jsfiddle.net/kevinPHPkevin/p4sA3/19/
.bunch {
position: absolute;
text-align:center;
left:0;
right:0;
}

Answer 2

Solution:
#total-wrap {
border:1px solid #000;
height:500px;
}
#box {
display:inline-block;
width:300px;
height:100px;
background-color:yellow;
margin:10px;
text-align:center;
}
.bunch {
text-align:center;
}

Answer 3

<div id="wrap">
<div id="left">Box1</div>
<div id="right">Box2</div>
</div>
#wrap {
background: #e7e7e7;
padding: 40px;
text-align: center;
width: auto;
}
#left, #right {
background: yellow;
display: inline-block;
padding: 20px;
}

Answer 4

Is this what you want?
#box {
position:relative;
display:inline-block;
width:100px;
height:100px;
background-color:yellow;
margin:10px;
}
DEMO: http://jsfiddle.net/p4sA3/11/
The thing is that as long the sum of the widths exceeds the container, the second div will be positioned beneath the first one
In this other demo I didn't use width: http://jsfiddle.net/p4sA3/13/

Answer 5

If you want to use jQuery:
Demo
keepCentered = function() {
$('#hello-wrap').css({'margin-left':($('#total-wrap').width()-$('#hello-wrap').width())/2});
$('#goodbye-wrap').css({'margin-left':($('#total-wrap').width()-$('#goodbye-wrap').width())/2});
}
$(document).ready(keepCentered);
$(window).bind('resize', keepCentered);