Page Fills Window With Content Filling The Gap

I am currently building a website at http://grapevineiow.org/m_inspireblog.html. This website has a header and footer. The page I have linked to above features a blog in an iframe.

Solution 1:

If you know the heights of the header and footer, you can achieve this by setting both top and bottom on the middle area like this:

<style type="text/css">
html, body{
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}
#header{
    position: absolute;
    top: 0;
    width: 100%;
    height: 100px;
    background: #f09;
}
#content{
    position: absolute;
    width: 100%;
    top: 100px;
    bottom: 100px;
    background: #f90;
}
#content iframe{
    width: 100%;
    height: 100%;
}
#footer{
    position: absolute;
    bottom: 0;
    width: 100%;
    height: 100px;
    background: #90f;
}
</style>

<div id="header"></div>
<div id="content">
    <iframe src="http://en.wikipedia.org/wiki/Butterfly"></iframe>
</div>
<div id="footer"></div>