Magic Map Not Working
If the Magic Map doesn't open at the requested location and/or produces an error that includes the message "Unexpected identifier 'denied'" then this is likely to be due to a security enhancement in the browser's handling of cookies. Basically, the Magic Map is now unable to set its cookies in an iframe as the Magic Map has not specified that this is allowable. For technical details please see this page.
The latest versions of Google Chrome and Microsoft Edge have this enhanced handling which results in the Magic Map not working when it's loaded in an html iframe (which is how Magic MapIt! loads it). Currently Firefox doesn't have this enhancement and therefore allows the Magic Map to operate correctly in an html iframe. At some point in the future Firefox will 'catch-up' with Google Chrome and Microsoft Edge and also include the same enhancement.
Solution
The only viable solutions to this issue are to either:- Set a browser option, if one is available, to allow the Magic Map to set its cookies when loaded in an iframe, or
- To use a browser extension that can modify Magic Map cookie requests to add the required cookie flags (namely "SameSite=None" and "Secure") to allow the cookies to be set in an iframe
Firefox currently has a browser option that allows the cookie restrictions to be relaxed for specific domains. Therefore, it's expected that when Firefox implements the cookie security enhancement a simple browser option change can be made. For Google Chrome and Microsoft Edge, no such option appears to be available and these browsers require an extension to be used. One extension that has been tested with these browsers is the HiFrame extension. The extension only modifies html request headers and doesn't examine the contents of any webpage it's used on.
The following sections detail how each browser can be modified to allow Magic MapIt! to use the Magic Map.
Google Chrome
Go to the HiFrame - The Hyper IFRAME extension! page and:
- Click 'Add to Chrome'
- Click 'Add extension'
After installation the extension can be accessed and managed by clicking the 'jigsaw piece' icon in the Toolbar. If you wish the make the extension visible in the Toolbar then click 'pin' next to 'HiFrame ...' and it will be pinned to the Toolbar. The default operation of the extension is to work on all websites; however, it's recommended to limit its operation to just the Magic Map website. To do this:
- Click on the 'three dots' next to the extension icon, or click on the icon if you've pinned it to the toolbar
- Click 'Manage Extension'
- Under 'Site access' change 'On all sites' to 'On specific sites'
- Enter https://magic.defra.gov.uk
- Click 'Add'
Magic MapIt! should now be able to load the Magic Map correctly.
Microsoft Edge
The installation instructions for Microsoft Edge are the same as those for the Google Chrome installation detailed above. Note however, if you see a message at the top of the extension page saying "You can now add extensions from the Chrome Web Store to Microsoft Edge", you will need to click on the 'Allow extension from other stores', and then click 'Allow' before the extension can be installed.
Firefox
Note: Only follow these instructions if the Magic Map stops working in Firefox.
- Enter about:config in the URL bar
- Click 'Accept the Risk and Continue'
- Enter network.cookie.sameSite.laxByDefault.disabledHosts in the search field
- Click the pencil icon
- Enter magic.defra.gov.uk in the entry box
- Click the 'tick' box.
Magic MapIt! should now be able to load the Magic Map correctly.