Install on this device
Chrome or Edge: use the install control in the address bar or browser menu. iPhone or iPad: open the browser Share menu, then Add to Home Screen. On recent macOS Safari, use File → Add to Dock. If your browser has no install option, keep using this tab.
Export a backup before installation. An installed app can use separate storage; restore the backup if your work is absent. Keep the same app address. Browser cleanup can remove local work. A local computer address (127.0.0.1) works only on that computer. A phone needs an approved HTTPS address; a computer LAN address over HTTP does not enable offline installation.