<script>
function sum() {
var txtFirstNumberValue = document.getElementById('textone').value;
var txtSecondNumberValue = document.getElementById('texttwo').value;
var result = parseInt(txtFirstNumberValue) + parseInt(txtSecondNumberValue);
if (!isNaN(result)) {
document.getElementById('textthree').value = result;
}
}
</script>
<script>
function sum() {
var txtFirstNumberValue = document.getElementById('textone').value;
var txtSecondNumberValue = document.getElementById('texttwo').value;
var result = parseInt(txtFirstNumberValue) + parseInt(txtSecondNumberValue);
if (!isNaN(result)) {
document.getElementById('textthree').value = result;
}
}
</script>
i try with all possibilities but result not came
echo '<td id="textone">'.$row['fee']. '</td>';
echo '<td id="texttwo" align="center"><input type="number" min="0" max="999" name="cnt" value="0" onkeyup="sum();"></td>';
echo '<td> <input type="text" name="result" id="result"></td>';
<script src="//ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
<script>
function sum() {
var txtFirstNumberValue = document.getElementById('textone').value;
var txtSecondNumberValue = document.getElementById('texttwo').value;
var result = parseInt(txtFirstNumberValue) + parseInt(txtSecondNumberValue);
if (!isNaN(result)) {
document.getElementById('result').value = result;
}
}
</script>