javascript-basics/factororial.html at main · DEMiHAT/javascript-basics · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
<!DOCTYPE html>
<html>
<head>
    <title>Factorial of a Number</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            background-color: #121212;
            color: white;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
        }
        .container {
            background: #1e1e1e;
            padding: 30px;
            border-radius: 10px;
            box-shadow: 0 0 10px rgba(255, 255, 255, 0.1);
            text-align: center;
        }
        input[type="number"] {
            padding: 8px;
            border-radius: 5px;
            border: none;
            width: 100px;
            text-align: center;
        }
        input[type="button"] {
            background-color: #007bff;
            color: white;
            border: none;
            padding: 8px 15px;
            border-radius: 5px;
            cursor: pointer;
            margin-left: 10px;
        }
        input[type="button"]:hover {
            background-color: #0056b3;
        }
        #result {
            margin-top: 15px;
            font-size: 18px;
            color: #00ffcc;
        }
    </style>
</head>
<body>

<div class="container">
    <h2>Factorial Calculator</h2>
    <form>
        <label>Enter a number:</label><br><br>
        <input type="number" id="num" min="0" placeholder="e.g. 5">
        <input type="button" value="Find Factorial" onclick="findFactorial()">
    </form>
    <p id="result"></p>
</div>

<script>
    function findFactorial() {
        let n = document.getElementById("num").value;
        n = parseInt(n);
        let fact = 1;

        if (isNaN(n) || n < 0) {
            document.getElementById("result").innerHTML = "⚠️ Please enter a valid non-negative number.";
            return;
        }

        for (let i = 1; i <= n; i++) {
            fact *= i;
        }

        document.getElementById("result").innerHTML = `✅ Factorial of ${n} is: <b>${fact}</b>`;
    }
</script>

</body>
</html>