No answer yet, but keeping an eye on this one.
Is there a way through JavaScript to detect if a Safari Extension is already installed? https://extensions.apple.com has some way of doing it because they update the install link to "installed" if the extension is already installed.
Someone's not happy...
A post on Reddit from the author of the Reddit Enhancement Suite Safari Extension.
Summary: He's not pleased with Apple's extension documentation or support
Safari 5, the latest version of Apple's web browser, introduces extensions. Safari extensions are small add-ons that you can use to expand Safari's
The Blockers: Extension and Plugins that Block Ads and...
1Password Safari 5.1 News & Updates