JavaScript implements simple calculator function

This article shares the specific code of JavaScript to implement a simple calculator for your reference. The specific content is as follows

This example is a simple calculator:

Code example:

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Simple Calculator</title>
    <script>
        var choice = prompt('Welcome to the simple calculator:\n1. Addition;\n2. Subtraction;\n3. Multiplication;\n4. Division;\n5. Exit;\nPlease enter your option:');
        switch (choice) {
            case '1':
                add();
                break;
            case '2':
                sub();
                break;
            case '3':
                multiplication();
                break;
            case '4':
                division();
                break;
            case '5':
                alert('Exited')
                break;
        }

        // add function add() {
            var num = prompt('Please enter the number of numbers to be added:');
            var sum = 0;
            var arr = [];
            for (var i = 0; i < num; i++) {
                arr[i] = prompt('Please enter the value of the ' + (i + 1) + ' number: ');
                console.log(arr[i]);
                sum += parseFloat(arr[i]);

                /* 
                Note: This way of writing can assign values to the arr array, but you cannot call arr[arr.length], as the result of the call is undefined
                arr[arr.length] = prompt('Please enter the value of the ' + (i + 1) + ' number: ');
                console.log(arr[arr.length]);
                sum += parseFloat(arr[arr.length]); 
                */
            }
            alert(arr + 'The sum of these numbers is:' + sum);
        }

        // subtraction function sub() {
            var number1 = prompt('Please enter the first value:');
            var number2 = prompt('Please enter the second value:');
            var result = parseFloat(number1) - parseFloat(number2);
            alert(number1 + 'minus' + number2 + 'the value is:' + result);
        }

        // multiplication function multiplication() {
            var number1 = prompt('Please enter the first value:');
            var number2 = prompt('Please enter the second value:');
            var result = parseFloat(number1) * parseFloat(number2);
            alert(number1 + ' multiplied by ' + number2 + ' is: ' + result);
        }

        // In addition to function division() {
            var number1 = prompt('Please enter the first value:');
            var number2 = prompt('Please enter the second value:');
            var result = parseFloat(number1) / parseFloat(number2);
            alert(number1 + 'divided by' + number2 + 'the value is:' + result);
        }
    </script>
</head>

<body>

</body>

</html>

Note: Try to use arr[arr.length] to assign and calculate, but you can only assign, not call. The call shows that the value of arr[arr.length] is undefined

Page effect:

add:

reduce:

take:

remove:

quit:

The above is the full content of this article. I hope it will be helpful for everyone’s study. I also hope that everyone will support 123WORDPRESS.COM.

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