Web Storage is a feature in HTML5 that allows you to store data on the client-side, persisting even when the user closes the browser. There are two types of Web Storage: localStorage and sessionStorage. Here are some ways to use Web Storage in HTML5:

1. Storing Data:

   You can store key-value pairs using setItem method:

   javascript
   // Using localStorage
   localStorage.setItem('key', 'value');
   
   // Using sessionStorage
   sessionStorage.setItem('key', 'value');
   

2. Retrieving Data:

   Retrieve the stored data using the getItem method:

   javascript
   // Using localStorage
   var storedValue = localStorage.getItem('key');
   
   // Using sessionStorage
   var storedValue = sessionStorage.getItem('key');
   

3. Removing Data:

   You can remove a specific item using the removeItem method:

   javascript
   // Using localStorage
   localStorage.removeItem('key');
   
   // Using sessionStorage
   sessionStorage.removeItem('key');
   

4. Clearing All Data:

   To clear all stored data, you can use the clear method:

   javascript
   // Using localStorage
   localStorage.clear();
   
   // Using sessionStorage
   sessionStorage.clear();
   

5. Handling Storage Events:

   You can listen for changes to the storage with the storage event:

   javascript
   window.addEventListener('storage', function (e) {
       // Handle storage changes here
   });
   

   This event is fired whenever localStorage or sessionStorage is modified in another window or tab.

6. Checking for Support:

   Before using Web Storage, it's a good idea to check if the browser supports it:

   javascript
   if (typeof(Storage) !== 'undefined') {
       // Web Storage is supported
   } else {
       // Web Storage is not supported
       // Handle the lack of support accordingly
   }
   

7. Using JSON for Complex Data:

   Web Storage stores data as strings, so if you want to store complex objects, you can use JSON.stringify and JSON.parse:

   javascript
   var complexObject = { key: 'value', nested: { prop: 'nestedValue' } };
   
   // Store complex object
   localStorage.setItem('complexObject', JSON.stringify(complexObject));
   
   // Retrieve complex object
   var retrievedObject = JSON.parse(localStorage.getItem('complexObject'));
   

Remember that while Web Storage is a convenient way to store small amounts of data on the client side, it's not suitable for storing sensitive information due to its accessibility to client-side scripts. For more secure storage options, consider using cookies or server-side storage.