Field Calculation after data submission

Hello, I have some problems in coding. Anybody please help me.


This is my web page and codes are as follows

export function button2_onclick(event, $w) {
if ($w(“#input3”).valid && $w(“#input13”).valid && $w(“#input11”).valid && $w(“#input6”).valid && $w(“#input8”).valid && $w(“#datePicker1”).valid && $w(“#dropdown1”).valid){
let balance = Number($w(‘#input15’).value);
let payamt = Number($w(‘#input8’).value);
$w(‘#input16’).value = Number(balance-payamt).toFixed(2);
$w(‘#dynamicDataset’).setFieldValue(‘credit’, $w(“#input16”).value);
$w(‘#dynamicDataset’).save();
$w(‘#dataset1’).setFieldValue(‘agentId’, $w(“#input5”).value);
$w(‘#dataset1’).setFieldValue(‘balance’, $w(“#input16”).value);
$w(‘#dataset1’).save();
$w(‘#dataset4’).setFieldValue(‘narration’, $w(“#text46”).text);
$w(‘#dataset4’).setFieldValue(‘amount’, $w(“#input8”).value);
$w(‘#dataset4’).setFieldValue(‘balance’, $w(“#input16”).value);
$w(‘#dataset4’).setFieldValue(‘agentId’, $w(“#input5”).value);
$w(‘#dataset4’).save();
}
}

#button2 is my SUBMIT button. When click on SUBMIT button, all data in Bill Payment form has saved in Cash Payment Database and successful message shown. Also some calculations were made back-end, But some time submit not successful and calculations were made. I want calculation done only when data submission successful. Please help me.