title: Is FILTER_SANITIZE_EMAIL pointless if already using FILTER_VALIDATE_EMAIL?
body: <p>I am just creating a registration form, and I am looking only to insert valid and safe emails into the database.</p>
  
  <p>Several sites (including w3schools) recommend running FILTER_SANITIZE_EMAIL before running FILTER_VALIDATE_EMAIL to be safe; however, this could change the submitted email from an invalid into a valid email, which could not be what the user wanted, for example:</p>
  
  <p>The user has the email address jeff!@gmail.com, but accidentally inserts jeff"@gmail.com.</p>
  
  <p>FILTER_SANITIZE_EMAIL would remove the " making the email jeff@gmail.com which FILTER_VALIDATE_EMAIL would say is valid even though it's not the user's actual email address.</p>
  
  <p>To avoid this problem, I plan only to run FILTER_VALIDATE_EMAIL. (assuming I don't intend to output/process any emails declared invalid)</p>
  
  <p>This will tell me whether or not the email is valid. If it is then there should be no need to pass it through FILTER_SANITIZE_EMAIL because any illegal/unsafe characters, would've already caused the email to be returned invalid, correct? </p>
  
  <p>I also don't know of any email approved as valid by FILTER_VALIDATE_EMAIL that could be used for injection/xss due to the fact that white spaces, parentheses () and semicolons would invalidate the email. Or am I wrong?</p>
  
  <p>(note: I will be using prepared statements to insert the data in addition to this, I just wanted to clear this up)</p>