What data does localstorage save?

Localstorage saves data such as strings, numbers, Boolean values, and objects. Detailed introduction: 1. String, the most commonly used data type of localstorage is string. Developers can use localstorage to save users’ personal information, setting options, user input, etc. as strings; 2. Numbers, localstorage can also save numeric types. For data, developers can use localstorage to save user preferences, counter values, etc.; 3. Boolean values, etc.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

Localstorage is an API for storing data in web browsers. It allows developers to save data in the user's browser so that it can be read and used the next time the user visits the website. data.

Localstorage can save many types of data, including strings, numbers, Boolean values ​​and objects. The uses and examples of each data type are detailed below.

1. String: The most commonly used data type in Localstorage is string. Developers can use Localstorage to save users' personal information, setting options, user input, etc. as strings. For example, an e-commerce website can use Localstorage to save the contents of a user's shopping cart so that the user can restore the previous shopping cart state the next time they visit.

Sample code:

localStorage.setItem('username', 'John');
localStorage.setItem('email', 'john@example.com');

2. Numbers: Localstorage can also save numeric type data. Developers can use Localstorage to save user preferences, counter values, etc. For example, a news website can use Localstorage to save a user's reading preferences to provide personalized news content the next time the user visits.

Sample code:

localStorage.setItem('fontSize', 16);
localStorage.setItem('themeColor', '#ffffff');

3. Boolean value: Localstorage can also save Boolean type data. Developers can use Localstorage to save users' login status, checkbox options, etc. For example, a social media site could use Localstorage to save a user's login status so that they can automatically log in the next time they visit.

Sample code:

localStorage.setItem('isLoggedIn', true);
localStorage.setItem('rememberMe', false);

4. Object: Localstorage can also save data of object type. Developers can use Localstorage to save complex data structures such as user configuration, application state, etc. For example, a task management application can use Localstorage to save user-created task lists.

Sample code:

const tasks = [
  { id: 1, title: 'Buy groceries', completed: false },
  { id: 2, title: 'Finish homework', completed: true },
  { id: 3, title: 'Go for a run', completed: false }
];
localStorage.setItem('tasks', JSON.stringify(tasks));

It should be noted that Localstorage can only save string type data. If you want to save other types of data, you need to use JSON.stringify() to convert it to a string, and then use JSON.parse() to convert it back to the original type.

To sum up, Localstorage can save many types of data, including strings, numbers, Boolean values ​​and objects. Developers can leverage Localstorage to save and read data in users' browsers to provide personalized user experiences and enhance application functionality. However, due to the limited storage space of Localstorage, developers should use it with caution and avoid saving too much data to avoid affecting performance and user experience.

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