Question

jsFiddle: http://jsfiddle.net/mYkjQ/

How do I make div2 + Button2 fill the rest of the window width?

Thank you.

CSS

td { border:solid 1px #000; float:left; }

#div1 { width:30%; border:solid 1px #000; float:left; }
#div2 { border:solid 1px #000; float:left; }
#div3 { width:30%; border:solid 1px #000; float:right; }

#Button1 { width:100% }
#Button2 { width:100% }
#Button3 { width:100% }

HTML

<div id="div1">
    <button id="Button1">Button 1</button>
</div>
<div id="div2">
    <button id="Button2">Button 2</button>
</div>
<div id="div3">
    <button id="Button3">Button 3</button>
</div>

Answer 1

The usual way to do it is to float all 3 div-s to left, and remove the border because on some browsers it would break because of that 1 pixel.

If you really need the border then do this:

<style type="text/css">
    #div1, #div3 { float:left; width:30%; }
    #div2 { float:left; width:40%; }
    #subdiv1, #subdiv2, #subdiv3 { border:solid 1px #000; }
    #Button1, #Button2, #Button3 { width:100% }
</style>

<div id="div1">
    <div id="subdiv1">
        <button id="Button1">Button 1</button>
    </div>
</div>
<div id="div2">
    <div id="subdiv2">
        <button id="Button2">Button 2</button>
    </div>
</div>
<div id="div3">
    <div id="subdiv3">
        <button id="Button3">Button 3</button>
    </div>
</div>

Edit1: jsfiddle for testing -> change the wrapper width to see that is scales to any width without breaking …