How to Keep JavaScript Variables Alive After a Page Refresh?

How Can JavaScript Variables Persist After Page Refresh?

The ability to retain the value of JavaScript variables even after refreshing a page is a common requirement in web development. Let's explore how to achieve this with the help of browser storage mechanisms.

Understanding Browser Storage

There are two main browser storage mechanisms that can be utilized:

• window.localStorage: Persistent storage that survives browser restarts and applies to the entire website.
• window.sessionStorage: Temporary storage that lasts as long as the browser session remains open.

Storing and Retrieving Variables

To set a variable in local storage, use:

localStorage.setItem("variableName", value);

To retrieve the variable's value after page refresh:

var retrievedValue = localStorage.getItem("variableName");

sessionStorage follows the same pattern, but its data is cleared once the browser session ends.

Additional Considerations

• Only string values can be stored directly in browser storage. Use JSON.stringify() to store more complex data types.
• There are size limitations imposed by browsers. Check browser documentation for details.
• It's recommended to abstract away the storage mechanisms using a custom library or use an existing one. This simplifies data handling regardless of the storage type.

Resources

• [Browser Storage Guide](https://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Storage)
• [localStorage](https://developer.mozilla.org/en-US/docs/DOM/Storage#localStorage)
• [JSON](https://developer.mozilla.org/en-US/docs/JSON)
• [Browser Storage Compatibility](http://caniuse.com/namevalue-storage)

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