How can I position a div at the very bottom of the page?

I have a simple div <div id="bottom"></div> that I want to position at the very bottom of the page. If I do

position: absolute;
bottom: 0%;

then it positions itself at the bottom of the visible portion of the page, not the actual bottom. And if I do

position: relative;
bottom: 0%;

it just stays in its default location. How can I place it at the very bottom?

Solution

Demo

html

<div id="container">
    <div id="header">
        <!-- Header start -->
        <h1>How to keep footers at the bottom of the page (CSS demo)</h1>
        <!-- Header end -->
    </div>
    <div id="body">
        <!-- Body start -->
        <p>In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal. Read the In this demo the footer is pushed to the bottom of the screen in all standards compliant web browsers even when there is only a small amount of content on the page. This with work with IE 6 and IE 5.5 too. Non-standards compliant browsers degrade gracefully by positioning the footer under the content as per normal.</p>
        <!-- Body end -->
    </div>
    <div id="footer">
        <!-- Footer start -->
        <p><strong>Footer</strong> (always at the bottom).</p>
        <!-- Footer end -->
    </div>
</div>

css

html, body {
    margin:0;
    padding:0;
    height:100%;
}
#container {
    min-height:100%;
    position:relative;
}
#header {
    background:#ff0;
    padding:10px;
}
#body {
    padding:10px;
    padding-bottom:60px;
    /* Height of the footer */
}
#footer {
    position:absolute;
    bottom:0;
    width:100%;
    height:60px;
    /* Height of the footer */
    background:#6cf;
}
/* other non-essential CSS */
 #header p, #header h1 {
    margin:0;
    padding:10px 0 0 10px;
}
#footer p {
    margin:0;
    padding:10px;
}

Note : If your body content is long enough your footer will be at the bottom of the page. If content is short enough it will stick at the bottom of screen.