js實現簡單四則運算計算器

時間 2019-11-12

原文原文鏈接

代碼以下：html

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>js計算器</title>
    <script>
        function calculator(){
            var num1 = parseFloat(document.getElementById("num1").value);
            var num2 = parseFloat(document.getElementById("num2").value);
            var result = parseFloat(document.getElementById("result").value);
            var mark = document.getElementById("mark").value;
            switch (mark){
                case "+" :
                    result = num1 + num2;
                    break;
                case "-" :
                    result = num1 - num2;
                    break;
                case "*" :
                    result = num1 * num2;
                    break;
                case "/" :
                    result = num1 / num2;
                    break;
            }
            document.getElementById("result").value = result;
        }
    </script>
</head>
<body>
    <input type="number" id="num1" >
    <select id="mark">
        <option> + </option>
        <option> - </option>
        <option> * </option>
        <option> / </option>
    </select>
    <input type="number" id="num2" >
    <button onclick="calculat0r()"> = </button>
    <input type="text" id="result" >
</body>
</html>

效果以下：spa

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