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Launch the Safari app on a Mac system.
Select Safari from the menu bar options.
Choose the Settings… option under the Safari menu.
Switch to the Websites tab within the popup window and choose Auto-Play in the sidebar.
Select the drop-down menu and your preferred choice. Selecting Allow All Auto-Play will allow auto-play with audio.
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To always allow auto-play with audio in Firefox:
Click the menu button
and select Settings.
Select the Privacy & Security panel and go to the Permissions section (or enter Auto-play in the Find in Settings search box).
Click the Settings… button next to Auto-play.
Use the Default for all websites drop-down menu to select how you want Firefox to handle media Auto-play for all websites.
The default Block Audio setting will prevent Auto-play for all media with sound.
Click Save Changes after you have made your selection.
The setting you have selected will apply to all media for all websites except for specific Auto-play site settings.
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