To enable JavaScript for all websites that you visit using Google Chrome, refer to the instructions under Step 1: Turn on JavaScript in the following article from Google Chrome Help:
To enable JavaScript and / or cookies, refer to the information in the relevant section below according to your web browser: This is because the Avast Store is unable to load and function correctly without these settings enabled.
When you make a purchase via the Avast Store, you may be notified that you need to enable JavaScript and / or cookies in your web browser. Enabling JavaScript and cookies in your web browser