add two numbers using textbox

$("[id*='Txt_MembersRegisteredFemale']").change(function () {

            var sum = parseInt($("[id*='Txt_MembersRegisteredFemale']").val(), 10) + parseInt($("[id*='Txt_MembersRegisteredMale']").val(), 10);
            $("[id*='totals']").val(sum);
        });

Use this code it will work

Try this code with optimization :

 

// Cache the elements to avoid multiple DOM lookups
var $txtMembersRegisteredFemale = $("[id*='Txt_MembersRegisteredFemale']");
var $txtMembersRegisteredMale = $("[id*='Txt_MembersRegisteredMale']");
var $totals = $("[id*='totals']");

// Use the input event instead of keyup to handle input changes
$txtMembersRegisteredFemale.on('input', function () {
    var sum = parseInt($txtMembersRegisteredFemale.val()) + parseInt($txtMembersRegisteredMale.val());
    $totals.val(sum).prop('disabled', true);
});

$txtMembersRegisteredMale.on('input', function () {
    var sum = parseInt($txtMembersRegisteredFemale.val()) + parseInt($txtMembersRegisteredMale.val());
    $totals.val(sum).prop('disabled', true);
});

 Try My Version also 

And in Code Behind

?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
           
        }

        public void Sum()
        {
            if (TextBox1.Text != "" && TextBox2.Text != "")
            {


                int v1 = Convert.ToInt32(TextBox1.Text);
                int v2 = Convert.ToInt32(TextBox2.Text);
                int v3 = v1 + v2;
                TextBox3.Text = Convert.ToInt32(v3).ToString();
            }

        }
        protected void TextBox3_TextChanged(object sender, EventArgs e)
        {
            Sum();
        }
       
        protected void TextBox1_TextChanged(object sender, EventArgs e)
        {
            Sum();
        }

        protected void TextBox2_TextChanged(object sender, EventArgs e)
        {
            Sum();
        }
    }
}

?

Sachin Singh

Actually this works

$("[id*='Txt_MembersRegisteredFemale']").change(function () {

            var sum = parseInt($("[id*='Txt_MembersRegisteredFemale']").val(), 10) + parseInt($("[id*='Txt_MembersRegisteredMale']").val(), 10);
            $("[id*='totals']").val(sum);
        });

But when i click on textbox 3 get the total value and its also editable, my scenerio is total value shown in textbox3 without clicking and its not editable

Yes , use jquery ,add jquery link on page then follow below

$("[id*='TextBox2']").change(function(){
 
var sum=parseInt($("[id*='TextBox2']").val(),10)+parseInt($("[id*='TextBox1']").val(),10);
$("[id*='TextBox3']").val(sum);
});

i use onkeyup

But not works, I need to any jquery link or anything else

Where i am doing wrong?