Chrome

1. In the upper right corner, click on the browser menu (with three lines) and select Settings.
2. Select Security and Privacy from the list, then click on Site Settings.
3. Scroll down to the Content section and click JavaScript.
4. Select Sites Can Use Javascript, if not already selected.  
5. Close the Settings tab.
6. Reopen the Chrome browser or click on the Reload this Page button of the web browser to refresh the page.

Firefox

1. In the address bar, type about:config and press Enter.
2. Click "Accept the Risk and Continue"  if a Proceed with Caution message appears.  
3. In the Search preference name box, search for JavaScript.enabled.
4. If JavaScript.enable is false, click the toggle button to the far right (image is two arrows pointing in reverse directions).
5. Close the Advance Preferences tab.  

Safari for Macintosh

1. Click Safari menu in the top left corner, then select Preferences.
2. Selet the Security tab.
3. In the Security tab, under the Web Content category click the Enable JavaScript box.
4. Click on the Reload the current page button.

Microsoft Edge for Windows

1. Click the "Settings and more" icon (ellipse [...] at the top-right of the Edge browser window).
2. Click Settings.
3. From the Settings menu, click Cookies and site permissions.
4. Scroll-down and click on JavaScript.
5. In the JavaScript window, toggle the slider to "on" or "allowed".
6. Close the Settings tab.
7. Refresh the page.