Question

I have three text boxes having ids: textbox1, textbox2, textbox3. I am retrieving values for first two textboxes from combo1.jsp by JSON and i want to add these two values and to display it on 3rd textboxes. Values of 1st textbox and 2nd textbox are coming from db, only i want to add these two values and to display in 3rd textbox.

  $("#combo1").change(function() {
$.getJSON('combo1.jsp', { combo1Val : $(this).val() }, function(data) {
 $("#textbox1").val(data.a);// suppose a's value came as 10 from db
$("#textbox2").val(data.b);// b's value came as 20 from db
 $("#textbox3").val(data.c);// here i want to show the sum(a+b) that is 30
});
});

Any ideas please?

Answer 1

Try this:

$("#combo1").change(function() {
    $.getJSON(
        'combo1.jsp', 
        { combo1Val : $(this).val() }, 
        function(data) {
            var a = data.a; // suppose a's value came as 10 from db
            var b = data.b; // b's value came as 20 from db
            var total = parseInt(a) + parseInt(b);

            $("#textbox1").val(a)
            $("#textbox2").val(b)
            $("#textbox3").val(total); // here i want to show the sum(a+b) that is 30
        }
    );
});

You can cut this down if required, I’ve just made it as clear as possible how it’s working.

UPDATE

To update the sum after changing either value, try this:

$("#textbox1, #textbox2").keyup(function() {
    var a = $("#textbox1").val();
    var b = $("#textbox2").val();
    var total = parseInt(a) + parseInt(b);
    $("#textbox3").val(total);
});