What is sessionstorage

sessionstorage is a storage mechanism provided by web browsers for storing and accessing data during a browser session. It is part of the HTML5 specification and provides a set of simple APIs that can be accessed through JavaScript. To operate sessionStorage, compared with localStorage, sessionStorage is temporary and only valid during the current session. It is very useful for storing session-related temporary data, such as user login information, shopping cart contents, etc.

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

sessionStorage is a storage mechanism provided by web browsers to store and access data during a browser session. It is part of the HTML5 specification and provides an easy way to store and retrieve data via a JavaScript API.

sessionStorage is similar to localStorage, but has some key differences. sessionStorage is only valid during the current browser session, that is, when the user closes the browser window or tab, the data stored in sessionStorage will be cleared. LocalStorage is persistent. Even if the browser is closed, the data stored in localStorage will always exist.

The use of sessionStorage is very simple. SessionStorage can be accessed and manipulated using the sessionStorage object in JavaScript. The following are some commonly used sessionStorage methods:

1. setItem(key, value): Store key-value pairs in sessionStorage. key is the key of the data to be stored, and value is the value of the data to be stored. For example:

sessionStorage.setItem('username', 'John');

The above code stores the username in sessionStorage with the key 'username' and the value 'John'.

2. getItem(key): Retrieve the value of the specified key from sessionStorage. For example:

var username = sessionStorage.getItem('username');
console.log(username); // 输出：John

The above code retrieves the value with the key 'username' from sessionStorage and assigns it to the variable username.

3. removeItem(key): Delete the data of the specified key from sessionStorage. For example:

sessionStorage.removeItem('username');

The above code will delete the data with the key 'username' from sessionStorage.

4. clear(): Clear all data in sessionStorage. For example:

sessionStorage.clear();

The above code will clear all data in sessionStorage.

sessionStorage also has some other features and usages:

1. Data type: sessionStorage can only store string type data. If you want to store other types of data, you need to convert it to a string first.

2. Scope: The scope of sessionStorage is limited to the current browser window or tab. The sessionStorage between different windows or tabs is isolated and does not affect each other.

3. Storage capacity: The storage capacity of sessionStorage is usually smaller than that of localStorage. Different browsers have limitations on the storage capacity of sessionStorage, which is usually 5MB or less.

4. Security: The data stored in sessionStorage is only stored on the client (browser) and will not be sent to the server. Therefore, it is not suitable for storing sensitive information.

In summary, sessionStorage is a storage mechanism provided by web browsers to store and access data during a browser session. It provides a simple set of APIs to operate sessionStorage through JavaScript. Compared with localStorage, sessionStorage is temporary and only valid during the current session. It is useful for storing session-related temporary data, such as user login information, shopping cart contents, etc. However, it should be noted that sessionStorage is not suitable for storing sensitive information and has limited storage capacity.

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