Prime number check

by Jayaraj J

HTML

<p>
    <label>Number <input type="text" id="input_num" />is it a prime?</label>
</p>

<p id="result"></p>

CSS

body { font: 100% "Helvetica Neue", sans-serif; }
p { margin: 0 0 10px 0; }
input { border: 1px solid #ccc; width: 80px; padding: 3px 5px; font: 100% "Helvetica Neue", sans-serif; text-align: center; }
p#result { padding: 5px 10px; }
.yep { background: lightgreen; }
.nope { background: pink; }
.nan { background: yellow; }

JavaScript

function isPrime(num) {
    var prime = num != 1;
    for(var i=2; i<num; i++) {
    console.log(i)
        if(num % i == 0) {
            prime = false;
            break;
        }
        console.log(i)
        
    }
    return prime;
}

function init() {
    var input = document.getElementById("input_num");
    var result = document.getElementById("result");
    input.onkeyup = function(e) {
        var val = this.value;
        if(val == "") {
            result.className = "";
            result.innerHTML = "";
            return;
        }
        if(/\D/.test(val)) {
            result.className = "nan";
            result.innerHTML = "Nur Zahlen, du Dösbaddel!";
        } else {
            result.innerHTML = isPrime(val) ? "Yep, und wie!" : "Nö, ist keine.";
            result.className = isPrime(val) ? "yep" : "nope";
        }
    };
}

window.onload = init;