<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" name="viewport" content="width=device-width, initial-scale=1"/> <link rel="stylesheet" type="text/css" href="css/bootstrap.css"/> </head> <body> <nav class="navbar navbar-default"> <div class="container-fluid"> </div> </nav> <div class="col-md-6 well"> <hr style="border-top:1px dotted;"/> <div class="col-md-6"> <div class="form-group"> <input type="number"class="form-control" id="number1" onkeyup="autoCalculate()" placeholder="Enter a number"/> </div> <div class="form-group"> <select id="symbol" class="form-control" onchange="autoCalculate()"> </select> </div> <div class="form-group"> <input type="number"class="form-control" id="number2" onkeyup="autoCalculate()" placeholder="Enter a number"/> </div> <div class="form-group"> <input type="text" class="form-control" id="answer" disabled="disabled"/> </div> </div> </div> </body> </html>
function autoCalculate(){ var number1 = document.getElementById('number1').value; var number2 = document.getElementById('number2').value; var symbol = document.getElementById('symbol').value if(number1 != "" && number2 != ""){ switch(symbol){ case "add": var digit1 = parseFloat(number1); var digit2 = parseFloat(number2); var total = digit1 + digit2; document.getElementById('answer').value = total; break; case "sub": var digit1 = parseFloat(number1); var digit2 = parseFloat(number2); var total = digit1 - digit2; document.getElementById('answer').value = total; break; case "mult": var digit1 = parseFloat(number1); var digit2 = parseFloat(number2); var total = digit1 * digit2; document.getElementById('answer').value = total; break; case "div": var digit1 = parseFloat(number1); var digit2 = parseFloat(number2); var total = digit1 / digit2; document.getElementById('answer').value = total; break; } }else{ document.getElementById('answer').value = ''; } }