BMIの判定器 【JavaScriptのサンプルコード】

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ここでは、当社の新人研修受講者に向けて、JavaScriptのサンプルコードを紹介しています。

BMIの判定器のサンプルコード

身長と体重からBMI(Body Mass Index)を判定します。

<!DOCTYPE html>
<html>
    <head>
        <title>BMI</title>
        <meta charset="UTF-8">
        <script>
            function calculate() {
                var h = document.getElementById("height").value;
                var w = document.getElementById("weight").value;
                var r = Math.round((w / (h * h)) * 10) / 10;
                var comment;
                var color;
                if (Number.isNaN(r)) {
                    comment = " please enter correctly ";
                    color = "red";
                } else if (r < 18.5) {
                    comment = " You are in the underweight.";
                    color = "blue";
                } else if (r < 25) {
                    comment = " You are in the normal range.";
                    color = "green";
                } else {
                    comment = " You are in the overweight.";
                    color = "yello";
                }
                document.getElementById('result').style.color = color;
                document.getElementById('result').textContent = "Your BMI is " + r + comment;
            }
        </script>

    </head>
    <body>
        <h1>Body Mass Index</h1>
        Height(m):<input id ="height"/><br>
        Weight(kg):<input id ="weight"/><br>
        <p><button onclick="calculate()">calculate</button></p>
        <p id ="result" ></p>
    </body>
</html>