Frontend & browser·Storage and platform APIs
you saved the preference and it was still there a week later, on that browser only.
localStorage
Also calledlocal storage, web storage
A synchronous key-value store of strings, scoped to the origin, with no expiry. It is convenient and it is synchronous on the main thread, which means a large read blocks rendering. It is readable by any script on the origin, so nothing sensitive belongs in it, and the accessor itself throws in some privacy modes, so every access needs wrapping.