How make middle div to fill space between floating elements?

Question

I have three div elements: left, middle and right. Left and right are fixed and floating. What I want is the middle div to fill the gap in between them.

Answer 1

The key is to restructure your html to have middle last, remove the float from the middle and replace it with overflow: hidden.

View fiddle example.

HTML

<div id="left"  >  left   </div>
<div id="right" >  right  </div>
<div id="middle">  middle </div>

CSS

#left {
    width: 200px;
    float: left;
}
#middle {
    overflow: hidden;
}
#right {
    width: 200px;
    float: right;
}

Answer 2

I was able to replicate the issue and fix it using percentages instead of absolute values. Since you are looking for something flexible between the two elements this should work.

#left {
    width: 20%;
    float: left;
    background: #ccc;
}
#middle {
    width: 60%;
    float: left;
    display: block;
    background: #ffffd;
}
#right {
    width: 20%;
    float: right;
    background: #bbb;
} 

Here's a demo