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js实现Bmi计算

2026-02-02 21:42:50JavaScript

以下是用JavaScript实现BMI计算的几种方法：

基础计算函数

function calculateBMI(weight, height) {
    const bmi = weight / (height * height);
    return bmi.toFixed(2);
}

完整BMI计算器（带分类）

function getBMICategory(bmi) {
    if (bmi < 18.5) return 'Underweight';
    if (bmi < 25) return 'Normal weight';
    if (bmi < 30) return 'Overweight';
    return 'Obese';
}

function fullBMICalculator(weightKg, heightM) {
    const bmi = calculateBMI(weightKg, heightM);
    const category = getBMICategory(bmi);
    return { bmi, category };
}

带单位转换的计算器

function calculateBMIWithUnits(weight, height, unitSystem = 'metric') {
    let weightKg = weight;
    let heightM = height;

    if (unitSystem === 'imperial') {
        weightKg = weight * 0.453592;  // 磅转千克
        heightM = height * 0.0254;    // 英寸转米
    }

    return calculateBMI(weightKg, heightM);
}

HTML页面集成示例

<!DOCTYPE html>
<html>
<head>
    <title>BMI Calculator</title>
</head>
<body>
    <div>
        <label>Weight (kg): <input type="number" id="weight"></label>
        <label>Height (m): <input type="number" id="height"></label>
        <button onclick="calculate()">Calculate BMI</button>
        <div id="result"></div>
    </div>

    <script>
        function calculate() {
            const weight = parseFloat(document.getElementById('weight').value);
            const height = parseFloat(document.getElementById('height').value);
            const result = fullBMICalculator(weight, height);
            document.getElementById('result').innerHTML = 
                `BMI: ${result.bmi} (${result.category})`;
        }
    </script>
</body>
</html>

使用时需要注意：