calculate text field on keypress
by lemon kazi
HTML
<tr>
<td><input type='text' name='qty' id='qty' value='' />
<td><input type='text' name='price' id='price' value='' />
<td><input type='text' name='total' id='total' value='' />
</tr>
JavaScript
$('#qty, #price').on('input',function() {
var qty = parseInt($('#qty').val());
var price = parseFloat($('#price').val());
$('#total').val((qty * price ? qty * price : 0).toFixed(2));
});