Simple Calculator Code in HTML Using JavaScript
What is a Simple Calculator in HTML/JavaScript?
A simple calculator built with HTML and JavaScript performs basic arithmetic operations directly in web browsers. This implementation features addition, subtraction, multiplication, division, decimal operations, and error handling for invalid inputs.
Calculator Formula and Explanation
The calculator uses JavaScript’s eval() function to process mathematical expressions with the following order of operations:
| Operation | Symbol | Precedence |
|---|---|---|
| Parentheses | () | Highest |
| Exponents | ** | High |
| Multiplication/Division | */ | Medium |
| Addition/Subtraction | +- | Low |
Practical Examples
Example 1: 15 + 7 × 3 = 36 (Multiplication before addition)
Example 2: (20 – 5) ÷ 2 = 7.5 (Parentheses first)
How to Use This Calculator
- Click number buttons to input values
- Select operators between numbers
- Press equals (=) to calculate
- Use (C) to clear
Key Functionality Factors
- Input validation
- Operator precedence handling
- Decimal point management
- Error detection
- Responsive design
- Cross-browser compatibility
FAQ
Does it handle complex equations?
Supports basic arithmetic only
How to add more operations?
Extend the button grid and calculation logic
Why use eval()?
Simplest implementation for basic operations