title: Checking Valid RSS feed URL
body: <p>I have decided to use SimplePie to parse RSS and Atom Feeds.</p>
  
  <p>What I want to do is that let people to input RSS and Atom Feeds URL through text fields.</p>
  
  <p>What If they put invalid RSS and Atom Feeds?</p>
  
  <p>I know that invalid Feeds won't be parsed through SimplePie.</p>
  
  <p>But I want to know whether the Feeds are able to be parsed through SimplePie or not.</p>
  
  <p>And through that process, I want to delete those invalid RSS feed URL lists.</p>
  
  <p>Checking the document type, XML or HTML will be a first step to find out the validness.</p>
  
  <p>How can I do that in PHP? or is there other ways to do what I want to do?</p>