Step 7 - Verify Your Store's Javascript
Step 7 must be performed manually after installation to verify that the extension is working correctly and to correct any troubleshooting errors.
Browse your store to verify no new Javascript errors have appeared.
If nothing comes up, Fooman Speedster is working as expected.
Any new errors are most likely caused by either trying to minify already minified files or minifying javascript files that do not follow best practice coding style for Javascript.
To fix the double minification problem, replace the already minified file with the original non-minified javascript. A javascript file with .min.js in its file name is always a sure sign that this file has been minified.
To find the origin of remaining Javascript errors, we suggest testing all Javascript files which are not part of the Magento base/default theme on jslint.com for code quality.