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Creating Captcha Code with JavaScript

By Mahak Gupta on Oct 25, 2010
In this article we will see how to create a captcha code with JavaScript.

Here I create a Captcha Code with JavaScript.

Step 1:

In the (.aspx) page we write the following Code:

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
<html xmlns="">
<head id="Head1" runat="server">
     <script language="javascript">
         var a = 49, b = 65;
         var c = 100;
         var d = 70;
         function show() {
             if (a == 57) {
                 a = 49;
             var main = document.getElementById('txt1');
             var a1 = String.fromCharCode(a);
             var b1 = String.fromCharCode(b);
             var c1 = String.fromCharCode(c);
             var d1 = String.fromCharCode(d);
             main.value = a1 + b1 + c1 + d1;
             a = a + 1;
             b = b + 1;
             c = c + 1;
             d = d + 1;
    <style type="text/css">
            height: 95px;
    <form id="form1" runat="server">
    <input type="text" id="txt1" runat="server"
            style="border-style: none; border-color: inherit; border-width: medium; background-color:black; color:red; font-family: 'Curlz MT'; font-size: x-large; font-weight: bold; font-variant: normal; letter-spacing: 10pt; width: 120px; background-image: url('glitter_background_b4.gif');"
            value="5AbD" />
  <input type="button" onclick="show()" value="Change"  />
    <asp:TextBox ID="txtverification" runat="server"></asp:TextBox>
    <asp:Button ID="Button1" runat="server" Text="Verification"
        onclick="Button1_Click" />
    <asp:Label ID="lblmsg" runat="server" Font-Bold="True" ForeColor="Red"></asp:Label>

Step 2:

In the (.cs) page I write the following code for verification:

protected void Button1_Click(object sender, EventArgs e)
    if (txtverification.Text == txt1.Value)
        lblmsg.Text = "Successful";
        lblmsg.Text = "Failure";

Mahak Gupta
Mahak Gupta

My name is Mahak Gupta. I am a C# Corner MVP.



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