Please recommend a web-app to view Microsoft Excel XLSX spreadsheets without downloading anything.
Looking for something that will run in a web browser (preferably Firefox) on a device that does not have user-writable storage.
Price needs to be gratis, and it is a requirement that no account/login is required.
All the spreadsheets are publicly available via HTTPS, so data privacy is not a concern.
Search functionality is a plus, but the browser's
find function is likely sufficient.