Learn about browser storage and caching methods in JavaScript

Understand browser storage and caching methods in JavaScript
In web development, the browser's storage and caching functions are very important. They improve user experience, reduce network requests, and increase page load speeds. In this article, we will discuss common browser storage and caching methods in JavaScript and give specific code examples.

1. Cookie
Cookie is a method for browsers to store data. It allows web servers to store small amounts of data in the browser and then send it to the server on subsequent requests. The following is a sample code for setting and getting Cookie:

// Set Cookie
document.cookie = "username=John Doe; expires=Sat, 31 Dec 2022 00:00:00 UTC; path= /";

// Get Cookie
function getCookie(name) {
var cookieArr = document.cookie.split("; ");
for(var i = 0; i

var cookiePair = cookieArr[i].split("=");
if(name === cookiePair[0]) {
  return decodeURIComponent(cookiePair[1]);
}

}
return null;
}

var username = getCookie("username");

二, LocalStorage
LocalStorage is a new method for browsers to store data in HTML5. It can save data in the browser for a long time, even if the user closes the browser or restarts the computer, the data will still be there. The following is a sample code to set and get LocalStorage:

// Set LocalStorage
localStorage.setItem("username", "John Doe");

// Get LocalStorage
var username = localStorage.getItem("username");

// Delete LocalStorage
localStorage.removeItem("username");

3. SessionStorage
SessionStorage is related to LocalStorage is similar to how browsers store data, but it is only valid in the current session. When the user closes the browser tab or browser, the data in SessionStorage will be cleared. The following is a sample code for setting and getting SessionStorage:

// Set SessionStorage
sessionStorage.setItem("username", "John Doe");

// Get SessionStorage
var username = sessionStorage.getItem("username");

//Delete SessionStorage
sessionStorage.removeItem("username");

4. IndexedDB
IndexedDB is a An advanced browser database storage method that can store large amounts of structured data in the browser. Unlike LocalStorage and SessionStorage, IndexedDB allows developers to create multiple databases and perform complex data operations. The following is a sample code using IndexedDB:

// Open the database
var request = window.indexedDB.open("myDatabase", 1);

request.onupgradeneeded = function( event) {
var db = event.target.result;
var objectStore = db.createObjectStore("customers", { keyPath: "id" });
};

/ / Add data
request.onsuccess = function(event) {
var db = event.target.result;
var transaction = db.transaction(["customers"], "readwrite");
var objectStore = transaction.objectStore("customers");
var customer = { id: 1, name: "John Doe" };
var request = objectStore.add(customer);

request.onsuccess = function(event) {

console.log("Data added successfully");

};
};

The above are some common browser storage and caching methods, including Cookie, LocalStorage, SessionStorage and IndexedDB . Choosing the appropriate method to store and obtain data based on needs and specific scenarios can improve user experience and web page performance. However, it should be noted that data security and privacy protection should be paid attention to when using these methods.

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