Follow the following steps to configure your Eclipse for using selenium.
1. Download the jar files from http://selenium-release.storage.googleapis.com/index.html
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2. Unzip the zip file and create a new project for selenium in your Eclipse.
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3. Right click on your project and make a new folder named lib
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4. Add the jar files to your project.
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5. Add all the jar files from the downloaded zip folder inside lib.
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6.Click on libraries and add the files and click on save and apply.
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All good and done. Completed. Now you can use selenium with your Eclipse.
Hope it was helpful.