MOZILLA FIREFOX (Windows/Mac)
To keep your browsing experience fast, reliable and secure, Firefox will not activate plugins by default. Instead, Firefox lets you choose whether or not to allow a plugin to run on a website.
On some sites, you’ll see just a blank rectangle, and the plugin notification icon will appear toward the left end of the address bar. If you click the message or the notification icon to activate the plugin, Firefox will prompt you:
Allow: Activates Flash only for a single visit. To automatically activate Flash for all future visits to that site, check the Remember this decision checkbox.
If you click to activate and allow the plugin, the missing content will load normally. (If it doesn’t, click the reload button in the toolbar to reload the page and try again.)