Confirm Email Address in onepage checkout in magento

Add one tax box in billing.phtml (app/design/frontend/ yourtheme/ yourtheme/template/checkout/onepage/billing.phl)

Ex : After email address Texbox add this :

<label for="billing:confirm_email" class="required"><em>*</em><?php echo $this->__('Re-Type Email Address') ?></label>

            <div class="input-box">

<input type="text" name="billing[confirm_email]" id="billing:confirm_email" value="<?php  $conf=$this->htmlEscape($this->getAddress()->getEmail()); echo $conf; ?>" onchange="abc(this.value)" title="<?php echo $this->__('Re-Type Email Address') ?>" class="input-text validate-email required-entry"  />

             </div>
  Then go to the onepage.php(code/core/Mage/Checkout/Model/Type)
In onepage.php do the following  change in function:


protected function _processValidateCustomer(Mage_Sales_Model_Quote_Address $address)
foreach (array( 
                         'firstname'    => 'firstname',

                         'lastname'     => 'lastname',

                        'email'        => 'email',

                        'confirm_email' => 'confirm_email',

                        'password'     => 'customer_password',

                        'confirmation' => 'confirm_password',

                        'taxvat'       => 'taxvat',

                        'gender'       => 'gender', )

 In elseif(self::METHOD_GUEST == $this->getQuote()->getCheckoutMethod())

  $email = $address->getData('email');

  $c_email=$address->getData('confirm_email');

           

  if($c_email != $email)

  {

        return array(

                              'error'   => -1,

                              'message' => $this->_helper->__('Not match email address "%s"', $c_email)

                           );

   }

                       

   if (!Zend_Validate::is($email, 'EmailAddress'))

  {

       return array(

                            'error'   => -1,

                            'message' => $this->_helper->__('Invalid email address "%s"', $email)

                          );

   }