72 lines
3.1 KiB
Markdown
72 lines
3.1 KiB
Markdown
---
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title: Store Data in Web Browsers Storage
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---
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In order to manage data handled by your web application, you do not necessarily need a database. The respective Browser Storage features are supported by Chrome (version 4 and higher), Mozilla Firefox (version 3.5 and higher) and Internet Explorer (version 8 and higher), and a range of other browsers including those of iOS and Android.
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There are two main possibilities for browser storage:
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## 1\. localStorage
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Any content/data saved to the `localStorage` object will be available after the browser has been restarted (closed and opened again). In order to **_save an item_** to `localStorage`, you can use the method `setItem()`. This method must be handed a key and a value.
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Example: localStorage.setItem("mykey","myvalue");
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To **_retrieve the item from the localStorage_**, the method `getItem` must be used. The `getItem` method must be handed the key of the data you would like to retrieve:
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Example: localStorage.getItem("mykey");
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You can remove an item from `localStorage` by using the `removeItem()` method. This method must be handed the key of the item to be removed:
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Example: localStorage.removeItem("mykey");
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To clear the entire `localStorage`, you should use the `clear()` method on the `localStorage` object:
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Example: localStorage.clear();
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## 2\. sessionStorage
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Items saved in the `sessionStorage` object will remain until the browser is closed by the user. Then, the storage will be cleared.
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You can save an item to `sessionStorage`, please use the method `setItem()` on the `sessionStorage` object:
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Example: sessionStorage.setItem("mykey","myvalue");
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To **_retrieve the item from the sessionStorage_**, the method `getItem` must be used. The `getItem` method must be handed the key of the data you would like to retrieve:
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Example: sessionStorage.getItem("mykey");
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You can remove an item from `sessionStorage` by using the `removeItem()` method. This method must be handed the key of the item to be removed:
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Example: sessionStorage.removeItem("mykey");
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To clear the entire `sessionStorage`, you should use the `clear()` method on the `sessionStorage` object:
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Example: sessionStorage.clear();
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## Saving arrays to localStorage and sessionStorage
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You cannot just save single values to the `localStorage` and `sessionStorage`, but you can also save the content of an array.
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In this example, we have an array with numbers:
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var ourArray =[1,2,3,4,5];
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We can now save it to `localStorage` or `sessionStorage` using the `setItem()` method:
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localStorage.setItem("ourarraykey",JSON.stringify(ourArray));
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or, for `sessionStorage`:
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sessionStorage.setItem("ourarraykey",JSON.stringify(ourArray));
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In order to be saved, the array must first be converted to a string. In the example shown above, we are using the `JSON.stringify` method to accomplish this.
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When retrieving our data from the `localStorage` or `sessionStorage`, convert it back to an array:
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var storedArray = localStorage.getItem("ourarraykey");
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ourArray = JSON.parse(storedArray);
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or, for `sessionStorage`:
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var storedArray = sessionStorage.getItem("ourarraykey");
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ourArray = JSON.parse(storedArray); |