Finding_Prime_Numbers/index.html at main · Kat-Bristol/Finding_Prime_Numbers · GitHub

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<!DOCTYPE html>
<html>

<head>
<title>Prime Number Finder</title>

<style>

body {
    font-family: Arial, sans-serif;
    text-align: center;
    margin-top: 80px;
}

.tool {
    width: 400px;
    margin: auto;
}

input, button {
    padding: 8px;
    font-size: 16px;
    margin: 5px;
}

#results {
    margin-top: 20px;
}

</style>

</head>

<body>

<div class="tool">

<h1>Prime Number Finder</h1>

<p>Enter a number range to find all prime numbers.</p>

<input id="start" type="number" placeholder="Start number">
<input id="end" type="number" placeholder="End number">

<br>

<button onclick="findPrimes()">Find Primes</button>

<p id="summary"></p>

<p id="results"></p>

</div>

<script>

function primesFinder(n) {

    let numberRange = [];
    for (let i = 2; i <= n; i++) {
        numberRange.push(i);
    }

    let primesList = [];

    while (numberRange.length > 0) {

        let prime = Math.min(...numberRange);

        numberRange = numberRange.filter(num => num !== prime);

        primesList.push(prime);

        let multiples = [];
        for (let i = prime * 2; i <= n; i += prime) {
            multiples.push(i);
        }

        numberRange = numberRange.filter(num => !multiples.includes(num));
    }

    return primesList;
}


function findPrimes() {

    let start = Number(document.getElementById("start").value);
    let end = Number(document.getElementById("end").value);

    if (start > end) {
    document.getElementById("summary").innerText = "Please make sure the start number is smaller than the end number.";
    return;
    }

    let allPrimes = primesFinder(end);

    let rangePrimes = allPrimes.filter(p => p >= start);

    document.getElementById("results").innerText = rangePrimes.join(", ");

    let primeCount = rangePrimes.length;

    if (primeCount > 0) {
        let largestPrime = Math.max(...rangePrimes);

        document.getElementById("summary").innerText =
        "There are " + primeCount + " prime numbers in this range. The largest is " + largestPrime + ".";
    }
    else {
        document.getElementById("summary").innerText =
        "No prime numbers found in this range.";
    }

}

</script>

</body>

</html>