user: i'm using sveltekit and whenever i try to use sessionStorage I get "access denied" error. it works on edge and chrome but doesn't work on opera GX. what's causing it? What do i need to do?

assistant: The "access denied" error you're experiencing with sessionStorage in SvelteKit is likely due to a security feature called "site isolation" that is enabled by default in Opera GX. Site isolation is a security feature that helps protect users from cross-site scripting (XSS) attacks by isolating web pages from each other.

To allow sessionStorage to work properly in Opera GX, you can disable site isolation for your SvelteKit app. Here's how to do it:

Open Opera GX and navigate to the following URL: opera://flags/#site-isolation-trial-opt-out
Click the "Disabled" option from the dropdown menu next to "Site isolation trial opt-out".
Restart Opera GX.
After disabling site isolation for your SvelteKit app, sessionStorage should work as expected. Keep in mind that disabling site isolation can reduce your security posture, so you may want to re-enable it once you're done using your app.

If you're still experiencing issues with sessionStorage after disabling site isolation, you may want to check that your SvelteKit app is running on HTTPS, as sessionStorage only works over HTTPS by default.

user: Thank you for your help, but unfortunately I tried this and it didn't help.

My SvelteKit app is running on HTTPS so can you suggest any additional help so I can resolve my issue?

Thanks.

assistant: The "access denied" error you're encountering with **sessionStorage** could be caused by a more restrictive Content Security Policy (CSP) setting in Opera GX.

To resolve this issue, you can try modifying your SvelteKit app's CSP header to allow **sessionStorage**.

Here's how you can do this:

1. In your SvelteKit app's **src/routes/__layout.svelte** file, add the following line inside the **<head>** element:  
`<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; font-src 'self'; img-src 'self' data:; connect-src 'self'; frame-src 'self'; object-src 'none'; media-src 'self'; worker-src 'self'; base-uri 'self'; form-action 'self'; manifest-src 'self'; frame-ancestors 'none'; frame-src 'none'; child-src 'self'; frame-ancestors 'none'; frame-src 'none'; sandbox allow-scripts allow-popups allow-forms allow-modals;">`  
Note that the above line contains the default CSP header for SvelteKit. You'll need to modify it according to your specific needs.  

2. Add **'unsafe-eval'** to the **script-src** directive, like this:  
`<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; font-src 'self'; img-src 'self' data:; connect-src 'self'; frame-src 'self'; object-src 'none'; media-src 'self'; worker-src 'self'; base-uri 'self'; form-action 'self'; manifest-src 'self'; frame-ancestors 'none'; frame-src 'none'; child-src 'self'; frame-ancestors 'none'; frame-src 'none'; sandbox allow-scripts allow-popups allow-forms allow-modals;">`

3. Add **'unsafe-hashes'** to the **script-src** directive, like this:  
`<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' 'unsafe-hashes'; style-src 'self' 'unsafe-inline'; font-src 'self'; img-src 'self' data:; connect-src 'self'; frame-src 'self'; object-src 'none'; media-src 'self'; worker-src 'self'; base-uri 'self'; form-action 'self'; manifest-src 'self'; frame-ancestors 'none'; frame-src 'none'; child-src 'self'; frame-ancestors 'none'; frame-src 'none'; sandbox allow-scripts allow-popups allow-forms allow-modals;">`

4. Add **'unsafe-inline'** to the **style-src** directive, like this:  
`<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' 'unsafe-hashes'; style-src 'self' 'unsafe-inline'; font-src 'self'; img-src 'self' data:; connect-src 'self'; frame-src 'self'; object-src 'none'; media-src 'self'; worker-src 'self'; base-uri 'self'; form-action 'self'; manifest-src 'self'; frame-ancestors 'none'; frame-src 'none'; child-src 'self'; frame-ancestors 'none'; frame-src 'none'; sandbox allow-scripts allow-popups allow-forms allow-modals;">`

5. Add **'unsafe-inline'** to the **child-src** directive, like this:  
`<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' 'unsafe-hashes'; style-src 'self' 'unsafe-inline'; font-src 'self'; img-src 'self' data:; connect-src 'self'; frame-src 'self'; object-src 'none'; media-src 'self'; worker-src 'self'; base-uri 'self'; form-action 'self'; manifest-src 'self'; frame-ancestors 'none'; frame-src 'none'; child-src 'self' 'unsafe-inline'; frame-ancestors 'none'; frame-src 'none'; sandbox allow-scripts allow-popups allow-forms allow-modals;">`

6. Finally, add **'unsafe-inline'** to the **connect-src** directive, like this:  
`<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' 'unsafe-hashes'; style-src 'self' 'unsafe-inline'; font-src 'self'; img-src 'self' data:; connect-src 'self' 'unsafe-inline'; frame-src 'self'; object-src 'none'; media-src 'self'; worker-src 'self'; base-uri 'self'; form-action 'self'; manifest-src 'self'; frame-ancestors 'none'; frame-src 'none'; child-src 'self' 'unsafe-inline'; frame-ancestors 'none'; frame-src 'none'; sandbox allow-scripts allow-popups allow-forms allow-modals;">`  
The above CSP header allows for **sessionStorage** to be used in your SvelteKit app in Opera GX.

Once you've added this CSP header to your app, clear your browser cache and try running your app again in Opera GX. **sessionStorage** should now work without any "access denied" errors.