How to disable Adobe Flash in your browser
Chrome
In Chrome, visit chrome://plugins/ to see a list of your plugins. Find Adobe Flash and select “disable.”
Firefox
Select “Add-ons” from the browser’s Tools menu to open the list of plugins. From there, find Shockwave Flash, and select “never activate.”
Alternatively, If there are certain websites you regularly use that require flash, you can select “ask to activate,” which allows you to choose when you want to enable it.
Safari
Open the Preferences tab (under the “Safari” menu) and select security. Select the “website settings options” next to the “Internet plug-ins” option. Choose Adobe Flash Player from the left-hand menu and select “block” from the drop-down menu on the right. Alternatively, if you sometimes need Flash, you can select “Ask,” which allows you to choose when to enable Flash.