How did they develop this website footer?

I understand how to show/hide DIV but how did they make this footer?

I would love this on my website.

Please take a look开发者_如何学C at this page it's Constant Contact by the way, notice the footer.

Constant Contact Thanks!

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Here is a very simplistic version of how to achieve something similar to your example. You only need to use JavaScript if you're using a browser < IE7, otherwise simple CSS can do it.

Live Demo

#footer{
  bottom: 0px;
  position: fixed;
}

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Give the div a fixed position. something like this:

<div style="width:100%; position:fixed; bottom:0px; background-color:blue; height: 50px;">
Excellent footer content here
</div>

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Looks like they used jQuery to animate the div that contains all the footer content.

The relevant .js file is here: http://www.constantcontact.com/_script/social-media-toolbar.js?version=1307033023000