How Can I Keep JavaScript Variable Values After Page Refresh?

Retaining JavaScript Variable Values on Page Refresh

In JavaScript, variables typically lose their values when the page is refreshed. To overcome this limitation, we can leverage the window.localStorage or window.sessionStorage methods.

window.localStorage

localStorage allows us to store key-value pairs that persist beyond browser restarts. It applies to the entire website, not just a single page.

To set a variable that should persist after a refresh, use:

var someVarName = "value";
localStorage.setItem("someVarKey", someVarName);

To retrieve the persisted value in any page, use:

var someVarName = localStorage.getItem("someVarKey");

window.sessionStorage

sessionStorage works similarly to localStorage but only persists data as long as the browser tab remains open. It's useful for temporarily storing session-specific information.

To use sessionStorage, replace localStorage with sessionStorage in the above examples.

Considerations:

• localStorage and sessionStorage can only store strings. To save non-string values, use JSON.stringify and JSON.parse.
• It's recommended to use a library or create your own abstraction to facilitate saving various data types.
• These methods provide site-wide persistence. Use them judiciously to avoid clutter and potential conflicts.

References:

• [DOM Storage](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)
• [Storing Objects in HTML5 localStorage](https://www.html5rocks.com/en/tutorials/storage/using-the-storage-api/)

The above is the detailed content of How Can I Keep JavaScript Variable Values After Page Refresh?. For more information, please follow other related articles on the PHP Chinese website!