SessionStorage Basics

Store and retrieve data in sessionStorage

BeginnerTopic: LocalStorage/SessionStorage
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JavaScript SessionStorage Basics Program

This program helps you to learn the fundamental structure and syntax of JavaScript programming.

Try This Code
// Method 1: Set item
sessionStorage.setItem('sessionId', 'abc123');
sessionStorage.setItem('pageViews', '5');
sessionStorage.setItem('lastPage', '/home');

// Method 2: Get item
const sessionId = sessionStorage.getItem('sessionId');
console.log('Session ID:', sessionId);

// Method 3: Remove item
sessionStorage.removeItem('pageViews');

// Method 4: Clear all
// sessionStorage.clear();

// Method 5: Store object
const sessionData = {
    userId: 123,
    username: 'John',
    loginTime: new Date().toISOString()
};

sessionStorage.setItem('sessionData', JSON.stringify(sessionData));

const storedData = JSON.parse(sessionStorage.getItem('sessionData'));
console.log('Session Data:', storedData);

// Method 6: Update page views
let pageViews = parseInt(sessionStorage.getItem('pageViews') || '0');
pageViews++;
sessionStorage.setItem('pageViews', pageViews.toString());
console.log('Page views:', pageViews);

// Method 7: Track navigation
function trackPage(page) {
    const history = JSON.parse(sessionStorage.getItem('pageHistory') || '[]');
    history.push({
        page: page,
        timestamp: new Date().toISOString()
    });
    sessionStorage.setItem('pageHistory', JSON.stringify(history));
}

trackPage('/home');
trackPage('/about');
trackPage('/contact');

const history = JSON.parse(sessionStorage.getItem('pageHistory'));
console.log('Page history:', history);

// Method 8: Temporary form data
function saveFormData(formData) {
    sessionStorage.setItem('formData', JSON.stringify(formData));
}

function getFormData() {
    const data = sessionStorage.getItem('formData');
    return data ? JSON.parse(data) : null;
}

// Save form data
saveFormData({
    name: 'John',
    email: '[email protected]',
    message: 'Hello'
});

// Retrieve form data
const formData = getFormData();
console.log('Form data:', formData);

// Method 9: Session timeout
function setSessionTimeout(minutes) {
    const expiry = new Date().getTime() + (minutes * 60 * 1000);
    sessionStorage.setItem('sessionExpiry', expiry.toString());
}

function isSessionValid() {
    const expiry = sessionStorage.getItem('sessionExpiry');
    if (!expiry) return false;
    
    return new Date().getTime() < parseInt(expiry);
}

setSessionTimeout(30); // 30 minutes
console.log('Session valid:', isSessionValid());

// Method 10: Clear on tab close
window.addEventListener('beforeunload', function() {
    // sessionStorage is automatically cleared when tab closes
    // But you can add cleanup code here
    console.log('Tab closing, sessionStorage will be cleared');
});
Output
Session ID: abc123
Session Data: { userId: 123, username: 'John', loginTime: '2024-01-01T12:00:00.000Z' }
Page views: 6
Page history: [
  { page: '/home', timestamp: '2024-01-01T12:00:00.000Z' },
  { page: '/about', timestamp: '2024-01-01T12:00:01.000Z' },
  { page: '/contact', timestamp: '2024-01-01T12:00:02.000Z' }
]
Form data: { name: 'John', email: '[email protected]', message: 'Hello' }
Session valid: true

Understanding SessionStorage Basics

sessionStorage stores data for one session.

Key Differences from localStorage

Cleared when tab closes
Tab-specific (not shared)
Same API as localStorage
Temporary storage

Use Cases

Session data
Form data (temporary)
Page navigation tracking
Temporary user state

Methods

Same as localStorage
setItem/getItem/removeItem
clear/key/length

When to Use

Temporary data
Tab-specific data
Session tracking
Form recovery

Best Practices

Use for temporary data
Clear when done
Handle tab close
Check expiry if needed

Let us now understand every line and the components of the above program.

Note: To write and run JavaScript programs, you need to set up the local environment on your computer. Refer to the complete article Setting up JavaScript Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your JavaScript programs.

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