Demo
<iframe height='265' scrolling='no' title='Prime Number' src='//codepen.io/fastfoodcoding/embed/zdzJOP/?height=265&theme-id=light&default-tab=result&embed-version=2' frameborder='no' allowtransparency='true' allowfullscreen='true' style='width: 100%;'>See the Pen <a href='https://codepen.io/fastfoodcoding/pen/zdzJOP/'>Prime Number</a> by fastfoodcoding (<a href='https://codepen.io/fastfoodcoding'>@fastfoodcoding</a>) on <a href='https://codepen.io'>CodePen</a>.
</iframe>
Code
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
$(document).ready(function() {
$("#btn").click(function() {
var number = $("#num").val();
output = "";
if (number == 1 || number == 2) {
$("#result").html("it's a prime number");
return;
}
for (i = 2; i <= number - 1; i++) {
if (number % i == 0) {
output = "it's not a prime number";
break;
} else {
output = "it's a prime number";
}
}
$("#result").html(output);
});
});
</script>
</head>
<body>
Enter a number:
<input type="text" name="value" id="num"></input>
<button id="btn"> Submit </button>
<h4>Output: </h4>
<span id="result"></span>
</body>
</html>