<!DOCTYPE html>
<html>
<head>
<style>
.calculator {
max-width: 300px;
margin: 0 auto;
border: 1px solid #ccc;
padding: 10px;
}
.output {
background-color: #f1f1f1;
text-align: right;
padding: 10px;
margin-bottom: 10px;
}
.buttons {
display: grid;
grid-template-columns: repeat(4, 1fr);
gap: 10px;
}
button {
padding: 10px;
font-size: 16px;
background-color: #3498db;
color: #fff;
border: none;
cursor: pointer;
transition: background-color 0.3s ease;
}
button:hover {
background-color: #2980b9;
}
</style>
</head>
<body>
<div class="calculator">
<div class="output" id="output">0</div>
<div class="buttons">
<button onclick="appendNumber('7')">7</button>
<button onclick="appendNumber('8')">8</button>
<button onclick="appendNumber('9')">9</button>
<button onclick="appendOperator('+')">+</button>
<button onclick="appendNumber('4')">4</button>
<button onclick="appendNumber('5')">5</button>
<button onclick="appendNumber('6')">6</button>
<button onclick="appendOperator('-')">-</button>
<button onclick="appendNumber('1')">1</button>
<button onclick="appendNumber('2')">2</button>
<button onclick="appendNumber('3')">3</button>
<button onclick="appendOperator('*')">*</button>
<button onclick="appendNumber('0')">0</button>
<button onclick="appendNumber('.')">.</button>
<button onclick="calculate()">=</button>
<button onclick="appendOperator('/')">/</button>
<button onclick="clearExpression()">C</button>
<button onclick="backspace()">⌫</button>
</div>
</div>
<script>
let outputDiv = document.getElementById('output');
let expression = '';
function appendNumber(number) {
expression += number;
outputDiv.innerText = expression;
}
function appendOperator(operator) {
if (expression.slice(-1) === '+' || expression.slice(-1) === '-' || expression.slice(-1) === '*' || expression.slice(-1) === '/') {
expression = expression.slice(0, -1);
}
expression += operator;
outputDiv.innerText = expression;
}
function calculate() {
try {
const result = eval(expression);
expression = result.toString();
outputDiv.innerText = expression;
} catch (error) {
// 处理错误
expression = '';
outputDiv.innerText = 'Error';
}
}
function clearExpression() {
expression = '';
outputDiv.innerText = '0';
}
function backspace() {
if (expression === '' || expression === '0') {
return;
}
if (expression.length === 1) {
expression = '0';
} else {
expression = expression.slice(0, -1);
}
outputDiv.innerText = expression;
}
</script>
</body>
</html>