sessionStorage is a client storage mechanism provided by HTML5. The data is only valid during the current session and will be cleared after closing the page or browser. It is suitable for temporary needs, such as multi-step form data storage, page status recording, etc. Operation methods include setting, reading, deleting and clearing data, but only string types can be stored, and objects or arrays need to be converted with JSON.stringify(). When using it, you should pay attention to cross-domain sharing, capacity limitation, low security, and inability to share across tabs. It is suitable for front-end interactive scenarios that save resources and improve user experience.

In web development, sessionStorage is a very practical tool if you need to temporarily save data during user sessions. It allows you to store key-value pair data in the user's browser, which is only valid during the current session and will be cleared after closing the page or browser. Compared to localStorage , it has a shorter life cycle, but is more suitable for temporary needs.

What is sessionStorage?

sessionStorage is a client storage mechanism provided by HTML5, similar to localStorage , but it has a key difference: data is only preserved in the current session . Once the user closes the browser tab or window, the data will be cleared. This makes it very suitable for saving some information that does not require long-term retention, such as form input, page status, etc.

The usage method is also relatively simple, and the basic operations include setting, reading, and deleting data:

• sessionStorage.setItem('key', 'value')
• sessionStorage.getItem('key')
• sessionStorage.removeItem('key')
• sessionStorage.clear()

It should be noted that the data in sessionStorage can only store string types. If you want to store objects or arrays, you need to convert them with JSON.stringify() before storing them.

Which scenarios are suitable for sessionStorage?

In many actual developments, we do not want to put all temporary data in memory or send it to the server. At this time, sessionStorage is very suitable.

for example:

• When filling in a multi-step form, the data of the intermediate step can be temporarily present in sessionStorage to avoid loss of refresh pages.
• When switching pages, the user selects the status, such as selected tabs, sorting methods, etc.
• Some operation records before the user logs in, such as products that have been added to the shopping cart but have not been logged in (of course, formal orders still have to rely on the server).

In this scenario, using sessionStorage not only saves resources but also improves user experience than frequently requesting servers.

What are the precautions when using it?

Although sessionStorage is simple and easy to use, there are some details that are easy to ignore:

• Cross-domain data is not shared : even if the two pages are the same but the ports are different, the data cannot be accessed from each other.
• Capacity limit : Most browsers support a size of about 5MB, and if it exceeds it, an error will be reported.
• Not very secure : Do not use it to store sensitive information, because data can be read by front-end scripts.
• Cannot share across tabs : Unlike localStorage , each tab has its own independent storage space.

In addition, if your application relies on sessionStorage to determine user status, remember to handle the data that does not exist to avoid errors.

Let's summarize

sessionStorage is a lightweight, limited life cycle local storage solution, especially suitable for temporary storage of session data. As long as you pay attention to the usage boundaries and limitations, you can serve the front-end interaction needs well. Basically all is it, not complicated but it is easy to ignore details.

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