Alternative to filter_var
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/13648117/filter-var-in-php-5-3-8">filter_var in php 5.3.8</a>  </p>
</blockquote>



<p>I recently upgraded to php 5.3.8 and I am having problem validating an email address a user enters into a registration form using "filter_var".
I want to ensure that when a valid email address is entered I post it to a database and if for some reason the format of the email address is incorrect I inform the user to enter a valid email address. 
So I checked php.net and it turns out filter_var does not exist in php 5.3.8
Does anyone know of an alternative to filter_var in php 5.3.8</p>
