How to implement data storage on H5 page production

H5 page data storage provides a variety of options to allow pages to store data and avoid amnesia after refresh. Common methods include: localStorage: permanently store string data, suitable for storing important and persistent data. sessionStorage: Temporarily store string data during the session, suitable for storing shopping cart products and other data that do not need to be saved for a long time. IndexedDB: Database-level storage, which can store a large amount of structured data, but the API is complex. The data format is unified into a string, and complex data needs to be converted in JSON. At the same time, pay attention to data security, error handling and multi-page synchronization.

H5 page data storage: those tips you may not know

Many friends asked me how to store data on the H5 page, and I think this thing is much more troublesome than native apps. In fact, this is not the case. As long as you master the method, H5's data storage can also be very good. In this article, let’s talk about the things about data storage on H5 pages, so that you can avoid some common pitfalls and write fast and stable code. After reading it, you can not only easily handle various data storage, but also improve your code taste.

Let me first talk about why I need to store data

H5 page data storage, to put it bluntly, let your page remember some things, such as the user's login status, the products in the shopping cart, or some personalized settings. Without data storage, your page is like an amnesia patient every time you refresh, and you don’t remember anything. The user experience is so bad.

Several commonly used storage methods

There are many ways to store data in H5, each with its advantages and disadvantages. Which one to choose depends on your needs.

• localStorage: This guy is a big shot in local storage, with a relatively large capacity (usually about 5MB, slightly different browsers). The data is saved permanently unless the user manually clears it or you delete it with code. Suitable for storing some more important data that needs to be saved for a long time, such as user preferences. However, it has a disadvantage, that can only store strings, and you need to handle the conversion of data formats yourself.

   <code class="javascript">// 存储数据localStorage.setItem('username', 'John Doe'); // 获取数据let username = localStorage.getItem('username'); console.log(username); // 输出: John Doe // 删除数据localStorage.removeItem('username');</code>

  Tips: The data of localStorage is shared across pages and can be accessed by all pages under the same domain name. If your page has multiple tab pages, pay attention to data synchronization.

• sessionStorage: This is very similar to localStorage, but the data is only valid during the current browser session. Close the browser tab or window and the data is gone. Suitable for storing temporary session data, such as items in the shopping cart. It also only supports string storage and requires processing data types by itself.

   <code class="javascript">// 存储数据sessionStorage.setItem('cart', JSON.stringify([{id: 1, name: 'apple'}, {id: 2, name: 'banana'}])); // 获取数据let cart = JSON.parse(sessionStorage.getItem('cart')); console.log(cart);</code>

  Tips: The data of sessionStorage is independent for each tab page, and the data between different tab pages will not be shared.

• Cookie: Old-fashioned storage technology, but it is used less now. It can set the expiration time and the data can be saved across browser sessions. However, cookies have very small capacity and are relatively low in security, which is prone to tampering. Cookies are not recommended to store large amounts of data unless there are special needs.

• IndexedDB: This thing is at the database level, can store a large amount of structured data, supports transaction processing, and has good performance. Suitable for storing large and complex data, such as offline caching. However, its API is relatively complex and difficult to get started.

   <code class="javascript">// IndexedDB 的使用比较复杂，这里就不展开详细代码了，需要学习它的API // 建议参考MDN文档学习IndexedDB的使用</code>

  Point tips: IndexedDB's API is relatively complex and requires careful learning and pay attention to error handling.

Selection of data format

Remember that localStorage and sessionStorage can only store strings. In order to store more complex data structures (such as objects and arrays), you need to use the JSON.stringify() method to convert the data into a string, and then parse it back with the JSON.parse() method.

Some suggestions

• Choose the right storage method and choose the most suitable storage method according to your data characteristics and needs.
• Pay attention to data security and do not store sensitive information, such as passwords, in localStorage or sessionStorage.
• Do a good job of error handling and deal with possible errors when reading data, such as the situation where the data does not exist.
• Consider data synchronization. If your application has multiple pages or multiple tab pages, consider data synchronization.

Okay, that’s all for sharing the knowledge about data storage on H5 pages. I hope this article can help you better understand and use the H5 data storage mechanism and write a better H5 page! Remember, practice brings true knowledge, and typing code more hands-on is the best way!

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