Add a Scroll to top button in the website footer.
This plugin adds a Scroll to top button in the footer of the WordPress website. It smoothly scrolls the website page on a single click. The icon will only appear when the height of the web page exceeds from a standard measure otherwise scroll icon will be invisible. The plugin gives you a varieties of icons to suit your website color. You can either select an icon or use it without icon with any background color. This plugin also comes with lot of options to customize the display of scroll button. Like the width and height of the icon can be customized, background color of the icon can be set if no icon is chooses. This is very simple plugin and compatible with wordpress version 3.0 to 3.5
You can find docs, FAQ and more detailed information about Ax ScrollTo Top on annupex.com. If you were unable to find the answer to your question on the FAQ or in any of the documentation, you should check the support forum on WordPress.org. If you can't locate any topics that pertain to your particular issue, post a new topic for it.
To know more about this plugin visit Ax ScrollTo Top
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Some of the scroll icon images are taken from http://office.microsoft.com/en-us/images/