Use these tips to make sure you get the correct versions of plug-ins.
Look for a “Plug-in missing” placeholder on the page: Click the “Plug-in missing” placeholder, then follow the onscreen instructions.
Look for a “[Plug-in] blocked for this website” placeholder on the page: To change plug-in blocking, choose Safari > Preferences, click Security, then click Plug-in Settings next to Allow Plug-ins. For more information about plug-in settings, see Security pane of Safari preferences.
Check the webpage for a recommendation: Websites often recommend the appropriate plug-in. If you can’t find a recommendation, contact the website’s owner.
Use plug-ins designed for an Intel processor: Your computer has an Intel processor and can use an Intel or Universal version of a plug-in (but not a PowerPC version).
View a list of your installed plug-ins: In Safari, choose Help > Installed Plug-ins.