How to add custom field in customer registration form in front end and admin end magento

let you want to add occupation for customer registration
1. Add the following code in the form tag in register.phtml and edit.phtml
app/design/frontend/default/yourstore/template/customer/form/register.html  

////////////////
 <div class="input-box">

                    <label for="occupation"><?php echo $this->__('Occupation') ?></label><br/>

                    <input type="text" name="occupation" id="occupation" value="<?php echo $this->htmlEscape($this->getFormData()->getOccupation()) ?>" title="<?php echo $this->__('Occupation') ?>" class="input-text" />

                </div> 

/////////////////

2. replace the following block of code in
app/code/core/Mage/Customer/Model/Resource/Setup.php 

//////////

 'group_id'           => array(

                        'type'               => 'static',

                        'label'              => 'Group',

                        'input'              => 'select',

                        'source'             => 'customer/customer_attribute_source_group',

                        'sort_order'         => 25,

                        'position'           => 25,

                        'adminhtml_only'     => 1,

                        'admin_checkout'     => 1,

                    ),     

///////////

with this
////////////

 'group_id'           => array(

                        'type'               => 'static',

                        'label'              => 'Group',

                        'input'              => 'select',

                        'source'             => 'customer/customer_attribute_source_group',

                        'sort_order'         => 25,

                        'position'           => 25,

                        'adminhtml_only'     => 1,

                        'admin_checkout'     => 1,

                    ),                   

                    'occupation'          => array(

                        'type'               => 'varchar',

                        'label'              => 'Occupation',

                        'input'              => 'text',

                        'sort_order'         => 7,

                        'validate_rules'     => 'a:2:{s:15:"max_text_length";i:255;s:15:"min_text_length";i:1;}',

                        'position'           => 120,

                    ),

///////////

3. find the following line of code around line 280  in
app/code/core/Mage/Customer/controllers/AccountController.php

///////
 $customerData = $customerForm->extractData($this->getRequest()); 
//////

and replace with
////////////
 $customerData = $customerForm->extractData($this->getRequest());

           //new code added to save occupation in database start here

            if($this->getRequest()->getParam('occupation'))

             {

                 $customer->setOccupation($this->getRequest()->getParam('occupation'));

                

             } 

              //new code added to save occupation in database end here

           

///////////

4. add the following code in
app/code/core/Mage/Customer/etc/config.xml 
your
under the customer_account

////////

<occupation>

                 <create>1</create>

                 <update>1</update>

              </occupation> 
//////

5. put this script in your register.phtml 's header file and remove it after one run
 <?php

  

     $setup = new Mage_Eav_Model_Entity_Setup('core_setup');

  

    $AttrCode = 'occupation';

  

      $settings = array (

  

          'position' => 1,

  

          'is_required'=> 0

  

      );

  

      $setup->addAttribute('1', $AttrCode, $settings);

  

      ?>

To show this field in admin end in customer tab field


1. find and replace this function of code in
app/code/core/Mage/AdminHtml/Block/Customers/Grid.php

/////////////////

 protected function _prepareCollection()

    {

        $collection = Mage::getResourceModel('customer/customer_collection')

            ->addNameToSelect()

            ->addAttributeToSelect('email')

            ->addAttributeToSelect('created_at')

            ->addAttributeToSelect('group_id')

            ->joinAttribute('billing_postcode', 'customer_address/postcode', 'default_billing', null, 'left')

             ->joinAttribute('billing_city', 'customer_address/city', 'default_billing', null, 'left')

            ->joinAttribute('billing_telephone', 'customer_address/telephone', 'default_billing', null, 'left')

            ->joinAttribute('billing_region', 'customer_address/region', 'default_billing', null, 'left')

            ->joinAttribute('billing_country_id', 'customer_address/country_id', 'default_billing', null, 'left');

        $this->setCollection($collection);

        return parent::_prepareCollection();

    } 
/////////////////// 

and replace with

//////////////////

 protected function _prepareCollection()

    {

        $collection = Mage::getResourceModel('customer/customer_collection')

            ->addNameToSelect()

            ->addAttributeToSelect('email')

            ->addAttributeToSelect('occupation')

            ->addAttributeToSelect('created_at')

            ->addAttributeToSelect('group_id')

            ->joinAttribute('billing_postcode', 'customer_address/postcode', 'default_billing', null, 'left')

             ->joinAttribute('billing_city', 'customer_address/city', 'default_billing', null, 'left')

            ->joinAttribute('billing_telephone', 'customer_address/telephone', 'default_billing', null, 'left')

            ->joinAttribute('billing_region', 'customer_address/region', 'default_billing', null, 'left')

            ->joinAttribute('billing_country_id', 'customer_address/country_id', 'default_billing', null, 'left');

        $this->setCollection($collection);

        return parent::_prepareCollection();

    } 
///////////////////  



2. find and replace this function of code in
app/code/core/Mage/AdminHtml/Block/Customers/Grid.php 


///////////

protected function _prepareColumns()

    {

        $this->addColumn('entity_id', array(

            'header'    => Mage::helper('customer')->__('ID'),

            'width'     => '50px',

            'index'     => 'entity_id',

            'type'  => 'number',

        ));

        $this->addColumn('firstname', array(

            'header'    => Mage::helper('customer')->__('First Name'),

            'index'     => 'firstname'

        ));

        $this->addColumn('lastname', array(

            'header'    => Mage::helper('customer')->__('Last Name'),

            'index'     => 'lastname'

        ));

       /* $this->addColumn('name', array(

            'header'    => Mage::helper('customer')->__('Name'),

            'index'     => 'name'

        ));*/

        $this->addColumn('email', array(

            'header'    => Mage::helper('customer')->__('Email'),

            'width'     => '150',

            'index'     => 'email'

        ));

        $this->addColumn('occupation', array(

            'header'    => Mage::helper('customer')->__('Occupation'),

            'width'     => '150',

            'index'     => 'occupation'

        ));

        $groups = Mage::getResourceModel('customer/group_collection')

            ->addFieldToFilter('customer_group_id', array('gt'=> 0))

            ->load()

            ->toOptionHash();

        $this->addColumn('group', array(

            'header'    =>  Mage::helper('customer')->__('Group'),

            'width'     =>  '100',

            'index'     =>  'group_id',

            'type'      =>  'options',

            'options'   =>  $groups,

        ));

        $this->addColumn('Telephone', array(

            'header'    => Mage::helper('customer')->__('Telephone'),

            'width'     => '100',

            'index'     => 'billing_telephone'

        ));

        $this->addColumn('billing_postcode', array(

            'header'    => Mage::helper('customer')->__('ZIP'),

            'width'     => '90',

            'index'     => 'billing_postcode',

        ));

        $this->addColumn('billing_country_id', array(

            'header'    => Mage::helper('customer')->__('Country'),

            'width'     => '100',

            'type'      => 'country',

            'index'     => 'billing_country_id',

        ));

        $this->addColumn('billing_region', array(

            'header'    => Mage::helper('customer')->__('State/Province'),

            'width'     => '100',

            'index'     => 'billing_region',

        ));

        $this->addColumn('customer_since', array(

            'header'    => Mage::helper('customer')->__('Customer Since'),

            'type'      => 'datetime',

            'align'     => 'center',

            'index'     => 'created_at',

            'gmtoffset' => true

        ));

        if (!Mage::app()->isSingleStoreMode()) {

            $this->addColumn('website_id', array(

                'header'    => Mage::helper('customer')->__('Website'),

                'align'     => 'center',

                'width'     => '80px',

                'type'      => 'options',

                'options'   => Mage::getSingleton('adminhtml/system_store')->getWebsiteOptionHash(true),

                'index'     => 'website_id',

            ));

        }

        $this->addColumn('action',

            array(

                'header'    =>  Mage::helper('customer')->__('Action'),

                'width'     => '100',

                'type'      => 'action',

                'getter'    => 'getId',

                'actions'   => array(

                    array(

                        'caption'   => Mage::helper('customer')->__('Edit'),

                        'url'       => array('base'=> '*/*/edit'),

                        'field'     => 'id'

                    )

                ),

                'filter'    => false,

                'sortable'  => false,

                'index'     => 'stores',

                'is_system' => true,

        ));

        $this->addExportType('*/*/exportCsv', Mage::helper('customer')->__('CSV'));

        $this->addExportType('*/*/exportXml', Mage::helper('customer')->__('Excel XML'));

        return parent::_prepareColumns();

    }

///////////////

3...find the following line of code in
app\code\core\Mage\Adminhtml\Block\Customer\Edit\Tab\Account.php 

/////

$suffixElement = $form->getElement('suffix');

        if ($suffixElement) {

            $suffixOptions = $this->helper('customer')->getNameSuffixOptions($customerStoreId);

            if (!empty($suffixOptions)) {

                $fieldset->removeField($suffixElement->getId());

                $suffixField = $fieldset->addField($suffixElement->getId(),

                    'select',

                    $suffixElement->getData(),

                    $form->getElement('lastname')->getId()

                );

                $suffixField->setValues($suffixOptions);

                if ($customer->getId()) {

                    $suffixField->addElementValues($customer->getSuffix());

                }

            }

        }

      

//////

and replace with
//////////////////////////////

$suffixElement = $form->getElement('suffix');

        if ($suffixElement) {

            $suffixOptions = $this->helper('customer')->getNameSuffixOptions($customerStoreId);

            if (!empty($suffixOptions)) {

                $fieldset->removeField($suffixElement->getId());

                $suffixField = $fieldset->addField($suffixElement->getId(),

                    'select',

                    $suffixElement->getData(),

                    $form->getElement('lastname')->getId()

                );

                $suffixField->setValues($suffixOptions);

                if ($customer->getId()) {

                    $suffixField->addElementValues($customer->getSuffix());

                }

            }

        }

        ///new code start here

         $fieldset->addField('occupation', 'text', array(

            'name'      => 'occupation',

             'label'=>'Occupation'

            

            ));

        

         ///new field end here

/////////////////////////////

4.find the follwing line of code around line no. 280 in file 
app\code\core\Mage\Adminhtml\controllers\CustomerController.php

///////////////

if (isset($data['subscription'])) {

                $customer->setIsSubscribed(true);

            } else {

                $customer->setIsSubscribed(false);

            }

 ////////////////

and replace with
///////////////

if (isset($data['subscription'])) {

                $customer->setIsSubscribed(true);

            } else {

                $customer->setIsSubscribed(false);

            }

           //new code added to save occupation in database start here

          

            if(isset($data['account']['occupation']))

             {

              

                 $customer->setData('occupation',$data['account']['occupation']);

                

             } 

             //new code added to save occupation in database end here

///////////////



Enjoy !!!!!!!!