<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<title>简单计算器</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
-webkit-tap-highlight-color: transparent;
}
body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background: linear-gradient(135deg, #1e3c72, #2a5298);
min-height: 100vh;
display: flex;
justify-content: center;
align-items: center;
padding: 16px;
}
.calculator {
background: #1a1a2e;
border-radius: 24px;
padding: 20px;
width: 100%;
max-width: 360px;
box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}
.display {
background: #0f0f1a;
border-radius: 16px;
padding: 20px;
margin-bottom: 20px;
text-align: right;
min-height: 90px;
display: flex;
flex-direction: column;
justify-content: flex-end;
word-break: break-all;
border: 1px solid #2a2a4a;
}
.expression {
color: #8a8ab0;
font-size: 16px;
min-height: 24px;
margin-bottom: 4px;
}
.result {
color: #ffffff;
font-size: 36px;
font-weight: bold;
line-height: 1.2;
}
.buttons {
display: grid;
grid-template-columns: repeat(4, 1fr);
gap: 12px;
}
button {
background: #16213e;
border: none;
border-radius: 16px;
color: #ffffff;
font-size: 22px;
font-weight: 600;
padding: 18px 0;
cursor: pointer;
transition: all 0.15s ease;
box-shadow: 0 4px 8px rgba(0,0,0,0.3);
user-select: none;
}
button:active {
transform: scale(0.95);
background: #1f3a5f;
}
.operator {
background: #2d4a7a;
}
.operator:active {
background: #3a5f96;
}
.equals {
background: #e94560;
color: white;
}
.equals:active {
background: #ff5d78;
}
.clear {
background: #b83232;
}
.clear:active {
background: #d84545;
}
.backspace {
background: #b83232;
}
.backspace:active {
background: #d84545;
}
.zero {
grid-column: span 2;
}
@media (max-width: 360px) {
.calculator {
padding: 12px;
}
.buttons {
gap: 8px;
}
button {
font-size: 18px;
padding: 14px 0;
}
.result {
font-size: 28px;
}
}
</style>
</head>
<body>
<div class="calculator">
<div class="display">
<div class="expression" id="expression"> </div>
<div class="result" id="result">0</div>
</div>
<div class="buttons">
<button class="clear" onclick="clearAll()">C</button>
<button class="backspace" onclick="backspace()">⌫</button>
<button class="operator" onclick="addOperator('%')">%</button>
<button class="operator" onclick="addOperator('/')">÷</button>
<button onclick="addNumber('7')">7</button>
<button onclick="addNumber('8')">8</button>
<button onclick="addNumber('9')">9</button>
<button class="operator" onclick="addOperator('*')">×</button>
<button onclick="addNumber('4')">4</button>
<button onclick="addNumber('5')">5</button>
<button onclick="addNumber('6')">6</button>
<button class="operator" onclick="addOperator('-')">-</button>
<button onclick="addNumber('1')">1</button>
<button onclick="addNumber('2')">2</button>
<button onclick="addNumber('3')">3</button>
<button class="operator" onclick="addOperator('+')">+</button>
<button class="zero" onclick="addNumber('0')">0</button>
<button onclick="addDot()">.</button>
<button class="equals" onclick="calculate()">=</button>
</div>
</div>
<script>
let expression = '';
let lastResult = null;
const expressionEl = document.getElementById('expression');
const resultEl = document.getElementById('result');
function updateDisplay() {
expressionEl.textContent = expression || ' ';
if (expression) {
// 尝试实时计算中间结果
try {
const val = evalExpression(expression);
if (val !== null && isFinite(val)) {
resultEl.textContent = formatNumber(val);
} else {
resultEl.textContent = '0';
}
} catch(e) {
resultEl.textContent = '0';
}
} else {
resultEl.textContent = (lastResult !== null) ? formatNumber(lastResult) : '0';
}
}
function formatNumber(num) {
if (Number.isInteger(num)) return num.toString();
// 避免浮点误差
const rounded = Math.round(num * 1e10) / 1e10;
return rounded.toString();
}
function evalExpression(expr) {
// 简单安全的表达式求值，只允许数字和运算符
if (!/^[0-9.\s+\-*/%]+$/.test(expr)) return null;
try {
// 处理百分号: 将 x% 替换为 x/100
let cleanExpr = expr;
// 使用 Function 代替 eval (同样有风险，但这里输入已过滤)
// 更安全：手动解析
return parseAndEval(cleanExpr);
} catch(e) {
return null;
}
}
// 手动解析四则运算，避免 eval 风险
function parseAndEval(expr) {
// 移除空格
expr = expr.replace(/\s+/g, '');
if (!expr) return null;
// 解析为 token
const tokens = [];
let numBuffer = '';
for (let i = 0; i < expr.length; i++) {
const ch = expr[i];
if ('0123456789.'.indexOf(ch) !== -1) {
numBuffer += ch;
} else if ('+-*/%'.indexOf(ch) !== -1) {
if (numBuffer === '' && (ch === '-' || ch === '+') && tokens.length === 0) {
numBuffer = ch;
continue;
}
if (numBuffer !== '') {
tokens.push(parseFloat(numBuffer));
numBuffer = '';
}
tokens.push(ch);
} else {
return null;
}
}
if (numBuffer !== '') tokens.push(parseFloat(numBuffer));
else return null;
// 处理百分号: 将 a% 变为 a/100
for (let i = 0; i < tokens.length; i++) {
if (tokens[i] === '%') {
if (i > 0 && typeof tokens[i-1] === 'number') {
tokens[i-1] = tokens[i-1] / 100;
tokens.splice(i, 1);
i--;
} else {
return null;
}
}
}
// 先乘除后加减
const stack = [tokens[0]];
for (let i = 1; i < tokens.length; i += 2) {
const op = tokens[i];
const num = tokens[i+1];
if (num === undefined) return null;
if (op === '*') {
stack.push(stack.pop() * num);
} else if (op === '/') {
if (num === 0) return Infinity;
stack.push(stack.pop() / num);
} else {
stack.push(op);
stack.push(num);
}
}
// 处理加减
let result = stack[0];
for (let i = 1; i < stack.length; i += 2) {
const op = stack[i];
const num = stack[i+1];
if (op === '+') result += num;
else if (op === '-') result -= num;
}
return result;
}
function addNumber(num) {
// 避免多个前导零
if (expression === '0' && num === '0') return;
if (expression === '0') {
expression = num;
} else {
expression += num;
}
updateDisplay();
}
function addOperator(op) {
if (!expression && lastResult !== null) {
// 从结果继续计算
expression = formatNumber(lastResult) + op;
lastResult = null;
} else if (expression) {
// 替换末尾运算符
const lastChar = expression[expression.length - 1];
if ('+-*/%'.indexOf(lastChar) !== -1) {
expression = expression.slice(0, -1) + op;
} else {
expression += op;
}
} else {
// 无输入，忽略
return;
}
updateDisplay();
}
function addDot() {
if (!expression) {
expression = '0.';
} else {
// 检查当前数字是否已有小数点
const parts = expression.split(/[+\-*/%]/);
const current = parts[parts.length - 1];
if (current.includes('.')) return;
expression += '.';
}
updateDisplay();
}
function calculate() {
if (!expression) return;
const result = parseAndEval(expression);
if (result === null || result === undefined) {
resultEl.textContent = '错误';
return;
}
if (!isFinite(result)) {
resultEl.textContent = '错误';
expression = '';
lastResult = null;
updateDisplay();
return;
}
const formatted = formatNumber(result);
expression = '';
lastResult = formatted;
expressionEl.textContent = '';
resultEl.textContent = formatted;
}
function clearAll() {
expression = '';
lastResult = null;
expressionEl.textContent = ' ';
resultEl.textContent = '0';
}
function backspace() {
if (expression.length > 0) {
expression = expression.slice(0, -1);
updateDisplay();
} else if (lastResult !== null) {
lastResult = null;
resultEl.textContent = '0';
}
}
// 键盘支持
document.addEventListener('keydown', function(e) {
const key = e.key;
if (key >= '0' && key <= '9') {
addNumber(key);
} else if (key === '.') {
addDot();
} else if (key === '+' || key === '-' || key === '*' || key === '/') {
addOperator(key);
} else if (key === '%') {
addOperator('%');
} else if (key === 'Enter' || key === '=') {
calculate();
} else if (key === 'Backspace') {
backspace();
} else if (key === 'Escape') {
clearAll();
}
e.preventDefault();
});
updateDisplay();
</script>
</body>
</html>