Convert String to Int Javascript

Question

Here i have some some form group with values from database

<div class="form-group">
 <label for="exampleInputTotalBayar">Total Bayar</label>
 <input type="text" class="form-control" id="inputTotalBayar" placeholder="Total Bayar" name="totalBayar" value="{{ $peminjaman->totalBayar }}">
</div>
<div class="form-group">
 <label for="exampleInputJumlahBayar">Jumlah Bayar</label>
 <input type="text" class="form-control" id="inputJumlahBayar" onchange="" placeholder="Jumlah Bayar" name="jumlahBayar" value="{{ $peminjaman->jml_bayar }}">
</div>

Then i want to give new values in this form

<div class="form-group">
 <label for="exampleInputDenda">Denda</label>
 <input type="text" class="form-control" id="exampleInputDenda" placeholder="Denda" name="denda" value="{{ $peminjaman->denda }}">
</div>

so, when i give new values in form group Denda, the output will be show in here

<p>Bayar Pengembalian: <div id="bayar" name="bayar"></div></p>

My code for javascript was like this

<script type="text/javascript">
var bayar = parseInt("0");
var totalBayar = parseInt($("#inputTotalBayar").val());
var jumlahBayar = parseInt($("#inputJumlahBayar").val());
var denda = parseInt($("#exampleInputDenda").val()); 
$("#exampleInputDenda").change(function() {
 bayar = bayar + denda + totalBayar - jumlahBayar; 
 $("#bayar").html(bayar);
});

but the calculation result doesn't appear, can you help me to solve this problem?

• Matías Fidemraizer: I find that this shouldn't be ever asked in SO... a quick search on the net would be enough to determine how to perform type conversions........
• Robby Cornelissen: Put your variable initialization inside your function.

Answer 1

You have to use

$("#exampleInputDenda").keyup(function() {
 var bayar = parseInt("0");
 var totalBayar = isNaN($("#inputTotalBayar").val()) ? 0 : parseInt($("#inputTotalBayar").val());
 var jumlahBayar = isNaN($("#inputJumlahBayar").val()) ? 0 : parseInt($("#inputJumlahBayar").val());
 var denda = isNaN($("#exampleInputDenda").val()) ? 0 : parseInt($("#exampleInputDenda").val());
 bayar = bayar + denda + totalBayar - jumlahBayar; 
 $("#bayar").html(bayar);
});

Error checking :)

Answer 2

Just change you event handler so you can get the values when the actual event happen like so - JSFiddle example

$("#exampleInputDenda").change(function() {
 var bayar = parseInt("0");
var totalBayar = parseInt($("#inputTotalBayar").val());
var jumlahBayar = parseInt($("#inputJumlahBayar").val());
var denda = parseInt($("#exampleInputDenda").val()); 
 var res = bayar + denda + totalBayar - jumlahBayar; 
 $("#bayar").html(res);
});

P.S Andd click Enter to actually see the new value!

Answer 3

see this with slide change of your code:

$(document).ready(function(){
 $("#exampleInputDenda").change(function(){
getValues();
});
// when using click event on button
 $("#me").click(function(){
 getValues();
 });
 });
function getValues(){
 var bayar = parseInt("0");
 var totalBayar = parseInt($("#inputTotalBayar").val());
 var jumlahBayar = parseInt($("#inputJumlahBayar").val());
 var denda = parseInt($("#exampleInputDenda").val()); 
 bayar = bayar + denda + totalBayar - jumlahBayar; 
 $("#bayar").html(bayar);
}
</script>

to see on click use this:

<button id="me" onclick='getValues()'>Click me!</button>