Hello JavaScript beginners and school / college students here is another interesting program that will help you to understand the basic concepts of JavaScript such as how to get a value from an input, How to print the value in a div etc.,
So this simple JavaScript program will tell you that the entered number is a Prime number or not!
Let’s see the program first, If you want to see the demo you can find the button at the end of this post.
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<!DOCTYPE html> <html> <head> <title>JavaScript to find prime number or not!</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <script> function findPrime(){ //get the input value var num = document.getElementById('num').value; var c = 0; //loop till i equals to $num for (i = 1; i <= num; i++) { //check if the $num is divisible by itself and 1 // % modules will give the reminder value, so if the reminder is 0 then it is divisible if (num % i == 0) { //increment the value of c c = c + 1; } } //if the value of c is 2 then it is a prime number //because a prime number should be exactly divisible by 2 times only (itself and 1) if (c == 2) { document.getElementById('result').innerHTML = num + ' is a Prime number'; }else{ document.getElementById('result').innerHTML = num + ' is NOT a Prime number'; } } </script> </head> <body> <h2>JavaScript to find Prime number or not!</h2> <form method="post"> Enter a number: <input type="number" id="num" name="num" min="0" /><input type="button" value="Find Prime Number" onclick="findPrime()" name="find" /> <div style="margin-top: 10px;" id="result"></div> </form> </body> </html> |
Go through code and read the comments in the above script to understand what each and every line of the JavaScript is doing.
You can see the demo here:
Thank you very much. it is very easy way to find prime number.