what is customer.form.register.fields.before and why this block add in customer_account_create?

Question

<reference name="content">
        <block type="customer/form_register" name="customer_form_register" template="customer/form/register.phtml">
            <block type="page/html_wrapper" name="customer.form.register.fields.before" as="form_fields_before" translate="label">
                <label>Form Fields Before</label>
            </block>
        </block>
</reference>

My qustion is what is customer.form.register.fields.before and why this block add in <customer_account_create> And

<?php echo $this->getChildHtml('form_fields_before')?>

what this code show in Phtml page.

Answer 1

By default this does nothing.
But it's there so you can add custom data before the register fields.
It acts like a container where you can put your stuff only by using the layout files.
Let's say you have this in one of your layouts.

<customer_account_create>
    <reference name="customer.form.register.fields.before">
        <block type="[module]/block_name" template="some/template.phtml" name="some_name" as="some_alias" />
    </reference>
</customer_account_create>

Then the block [module]/block_name will be rendered by the template some/template.phtml above the registration fields without any change to the customer register template itself/