Below is my Contact Form Email id Box :
<div class="field">
<label for="email" class="required"><em>*</em><?php echo Mage::helper('contacts')->__('Email') ?></label>
<div class="input-box">
<input name="email" id="email" title="<?php echo Mage::helper('contacts')->__('Email') ?>" value="<?php echo $this->escapeHtml($this->helper('contacts')->getUserEmail()) ?>" class="input-text required-entry validate-email" type="text" />
</div>
</div>
How can i give condition here like registered customer only submit enquiry form. this condition should check from my customer Database, if email id is not registered enforced to signup.
I am getting so many spam emails every day.