Javascript script to calculate n-th element of Triangle Numbers sequence.
// ? 2017 TheFlyingKeyboard and released under MIT License // theflyingkeyboard.net <html> <body> Enter a number: <input type="text" id="data"> <button onclick="calculate()">Convert</button> <p>Triangle Number is equal to</p> <p id="newText"></p> <script> function calculate(){ var data = document.getElementById("data").value; var n = parseInt(data); document.getElementById("newText").innerHTML = triangleNumber(n); } function triangleNumber(n) { return (n * (n + 1)) / 2; } </script> </body> </html>
Javascript Triangle Number