Web storage

Ramotion /Blog /What is Web Storage - Types, Tips & Use CasesLearn what is web storage: session, local, cookies, IndexedDB. Covers definitions, purposes, use cases, code snippets, tips, and real web development examples.Written by RamotionOct 30, 20239 min readLast updated: Feb 20, 2025Table of ContentsTypes of Web StorageWeb Storage Example Use CasesUsing the Web Storage APISecurityBrowser SupportConclusionWeb storage refers to client-side storage mechanisms that allow web apps to store data in the browser. This includes technologies like session storage, local storage, cookies, and IndexedDB.Web storage provides essential benefits for modern web applications by enabling data to persist between browser sessions and allowing pages to store data locally without contacting a server. Having storage available on the client side is crucial for many standard web features like shopping carts, game scores, user preferences, dynamic page content, and offline access to data. Web storage provides much more storage capacity compared to cookies and gives web app developers control over when data expires. Overall, web storage is an essential technology for building robust web apps that can store information locally while delivering a smooth user experience.Types of Web Storage1. Session StorageSession Storage allows data to be stored in the browser that will be cleared when the page session ends.The data stored in Session Storage persists only for the duration of the browser tab or window. When the tab or window is closed, the session storage is cleared.Some key aspects of Session Storage:The data is stored only for a session, meaning a browser tab.The

Can be personalized without requiring server-side user accounts.Shopping carts - E-commerce sites rely on web storage to implement persistent shopping carts that survive page reloads and crashes.Saving game state - Web-based games use web storage to save everything from high scores to character stats and progress.Session management - Web storage can store session IDs and other temporary data related to the user's visit.Caching resources - Static resources like images, CSS, and JS files can be cached and stored locally to improve page load speed.So, web storage opens up many possibilities like offline capability, speed improvements, personalization, and more. Any app that benefits from client-side data persistence can use the Web Storage API.Using the Web Storage APIThe Web Storage API provides mechanisms for storing data in the browser with key/value pairs. This data persists even after the browser window or tab is closed. The data is stored separately from cookies and has a larger storage capacity. There are two main web storage objects available:sessionStorage - stores data only for the current session. The data is deleted when the tab or window is closed.localStorage - stores data with no expiration date. The data persists until explicitly deleted.The Web Storage API is relatively simple to use. Here is an example of saving data to localStorage:// Save data to localStoragelocalStorage.setItem('myCat', 'Tom'); // Retrieve data from localStorageconst cat = localStorage.getItem('myCat'); CopyThe key things to note are:Data is saved as strings only. Numbers and booleans must be converted using JSON.stringify().Existing keys can be overwritten by calling

Prevent injection attacks.Avoid XSS vulnerabilities. Stored data could be vulnerable to XSS if output directly to the page. Encode any output from web storage.Through following security best practices, developers can safely leverage the benefits of web storage while mitigating risks. Being mindful of the client-side nature of web storage is critical.Browser SupportThe browser support for Web Storage APIs is generally good across modern browsers. Here are some key details:Session Storage and Local Storage have broad support in all primary desktop and mobile browsers, including Chrome, Firefox, Safari, Edge, and Opera. Cookies have near-universal support across major browsers.IndexedDB has good support across most modern browsers but lacks support in older browsers like IE10 and below.To handle limited browser support, polyfills and fallbacks can be implemented:LocalForage provides an IndexedDB polyfill that falls back to WebSQL and LocalStorage.A common fallback for SessionStorage is storing data in memory on the client side.Cookies can be a fallback for LocalStorage when browser support is limited.Web Storage enjoys broad support across browsers, but fallbacks should be implemented for maximum compatibility. The right polyfill brings IndexedDB support to older browsers. Cookies remain a tried and true storage mechanism with near-universal backing.ConclusionWeb storage is helpful in many common scenarios like storing user preferences, caching data to improve performance, and persisting data when offline. The Web Storage API provides simple synchronous key-value storage through localStorage and sessionStorage objects.When using web storage, it's essential to be mindful of browser support, security implications, and storage limits. Usage will likely grow as web

As web applications become increasingly sophisticated, the need to interact with browser-specific features like Local Storage has grown in importance. This comprehensive guide delves into the intricacies of working with Local Storage using Selenium in Python, offering insights and practical solutions for common challenges.Local Storage, a web browser feature that allows websites to store key-value pairs locally within a user's browser, has become an integral part of modern web applications (MDN Web Docs). With a larger storage capacity compared to cookies and persistence across browser sessions, Local Storage is ideal for storing user preferences, session data, and other client-side information.For Selenium users, interacting with Local Storage presents both opportunities and challenges. While Selenium doesn't provide direct methods to access Local Storage, creative use of JavaScript execution allows for robust interaction with this browser feature. This guide will explore various techniques, from basic operations to advanced practices, ensuring that you can effectively incorporate Local Storage handling into your Selenium-based Python scripts.We'll cover essential operations such as reading from and writing to Local Storage, handling JSON data, and implementing waiting mechanisms for asynchronous updates. Additionally, we'll delve into best practices for test automation, including maintaining clean states, error handling, and ensuring cross-browser compatibility. Advanced topics like secure handling of sensitive data, performance optimization for large-scale testing, and efficient clearing of storage will also be addressed.By the end of this guide, you'll have a comprehensive understanding of how to leverage Local Storage in your Selenium Python projects, enhancing your ability to create more powerful and efficient web automation and testing solutions.Accessing and Manipulating Local Storage with Selenium in Python​Understanding Local Storage in Web Browsers​Local Storage is a web browser feature that allows websites to store key-value pairs locally within a user's browser (MDN Web Docs). It provides a larger storage capacity (typically 5-10MB) compared to cookies (4KB) and persists even after the browser window is closed. This makes it ideal for storing user preferences, session data, and other client-side information.In the context of web automation and testing with Selenium, accessing and manipulating Local Storage can be crucial for various scenarios, such as:Verifying that an application correctly stores and retrieves data from Local StoragePre-populating Local Storage with specific data before running testsClearing Local Storage to ensure a clean state between test runsExtracting data stored in Local Storage for analysis or validationExecuting JavaScript to Interact with Local Storage​Selenium WebDriver doesn't provide direct methods to interact with Local Storage. However, we can leverage the execute_script() method to run JavaScript code that accesses the localStorage object (Stack Overflow). Here are some essential operations:Getting an item from Local Storage:def get_local_storage_item(driver, key): return driver.execute_script(f"return window.localStorage.getItem('{key}');")# Usagevalue = get_local_storage_item(driver, 'user_preferences')Setting an item in Local Storage:def set_local_storage_item(driver, key, value): driver.execute_script(f"window.localStorage.setItem('{key}', '{value}');")# Usageset_local_storage_item(driver, 'user_preferences', '{"theme": "dark", "language": "en"}')Removing an item from Local Storage:def remove_local_storage_item(driver, key): driver.execute_script(f"window.localStorage.removeItem('{key}');")# Usageremove_local_storage_item(driver, 'user_preferences')Clearing all items from Local Storage:def clear_local_storage(driver): driver.execute_script("window.localStorage.clear();")# Usageclear_local_storage(driver)Getting all items from Local Storage:def get_all_local_storage(driver): return driver.execute_script("return Object.assign({}, window.localStorage);")# Usageall_items = get_all_local_storage(driver)Handling JSON Data in Local Storage​Many applications store complex data structures as JSON strings