Web Storage
Web Storage gives your form scripts access to the browser's storage, so you can persist small pieces of data either for the current browser tab (session storage) or across browser sessions (local storage). It's available anywhere the standard script variables are available, alongside contexts such as formContext and pageContext.
Accessing Web Storage
Session storage is available at:
contexts.webStorage.session
Local storage is available at:
contexts.webStorage.local
Both give you an object with the same set of methods, so everything below applies equally to session and local. They wrap the browser's own sessionStorage and localStorage, but are not the native objects themselves - they add automatic JSON serialization on top.
Available Methods
| Method | What it does |
|---|---|
setItem(key, value) | Stores value under key. The value is automatically serialized with JSON.stringify, so you can store objects and arrays directly, not just strings |
getItem(key) | Retrieves the value stored under key, automatically parsed back from JSON into its original type |
removeItem(key) | Removes the value stored under key |
clear() | Removes everything stored |
key(index) | Returns the name of the key at the given position |
Unlike the browser's native localStorage/sessionStorage, contexts.webStorage.local.length and contexts.webStorage.session.length do not report how many items are stored. Reading .length is instead treated as looking up an item literally named length, so it will return null unless you have actually stored something under that key. If you need a count of stored items, track it yourself.
You can also read and write values directly by referring to them as named properties, instead of calling getItem/setItem explicitly:
contexts.webStorage.local.author = { name: 'Shesha' }; // same as setItem('author', { name: 'Shesha' })
const author = contexts.webStorage.local.author; // same as getItem('author')
Example
Form type to use: Edit Form - or any form type, since Web Storage is available everywhere standard script variables are.
Example - Save and read a value from local storage:
// values are serialized automatically, so objects and arrays are stored as-is
contexts.webStorage.local.setItem('author', { name: 'Shesha', role: 'admin' });
// getItem parses the stored JSON back into its original type
const author = contexts.webStorage.local.getItem('author');