added javascript project - Interactive Tip Calculator

[Saurabh-1785]

✅ Developer Checklist

• I have followed all the guidelines mentioned in the README file.
• I have maintained the required directory structure. (Format: ProjectName/{USERNAME}/...yourfiles)
• This Pull Request contains only one project.
• I have starred ⭐ the repository (optional).

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📝 Summary

Project: Interactive Tip Calculator

A clean, modern, and fully responsive web application for calculating tips and splitting bills among multiple people. The calculator provides real-time calculations with instant feedback and input validation.

Key Features:

• 💵 Enter bill amount with real-time validation
• 🎯 Quick tip selection (5%, 10%, 15%, 25%, 50%) or custom percentage
• 👥 Split bills among any number of people
• ⚡ Instant calculation updates
• 💸 Display tip amount and total per person in Indian Rupees (₹)
• ✅ Visual error highlighting for invalid inputs
• 🔄 One-click reset functionality
• 📱 Fully responsive design (mobile, tablet, desktop)

Technologies Used:

• HTML5 (Semantic markup)
• CSS3 (Flexbox, Grid, responsive design)
• Vanilla JavaScript (ES6+)

Changes Submitted:

• Complete tip calculator application with three core files
• Clean, modular code structure
• Comprehensive input validation
• Mobile-responsive design with media queries
• User-friendly interface with active state management

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📸 Screenshots / GIFs

Desktop View:

Full calculator layout with input section and results panel side by side

Mobile View

Full calculator layout with input section and results in mobile mode

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🔗 Live Project Link

Live Demo: https://saurabh-1785.github.io/interactive-tip-calculator/

Repository: https://github.com/saurabh-1785/interactive-tip-calculator

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💡 Additional Notes

Project Highlights:

• Zero dependencies - pure vanilla JavaScript
• Works offline once loaded
• Lightweight and fast loading
• Clean code with detailed comments
• Follows best practices for accessibility

Calculation Example:

Input:
- Bill Amount: ₹1000
- Tip Percentage: 15%
- Number of People: 4

Output:
- Tip per Person: ₹37.50
- Total per Person: ₹287.50

Testing:

• ✅ Tested on Chrome, Firefox, Safari, and Edge
• ✅ Validated on mobile devices (iOS & Android)
• ✅ Input validation thoroughly tested
• ✅ Edge cases handled (negative numbers, decimals, etc.)

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🎯 Future Enhancements (Optional)

• Add dark mode toggle
• Support multiple currencies
• Bill history/tracking feature
• Export/share calculation results
• Tip percentage recommendations based on service quality