title: PHP safely receiving user input
body: <p>I would like to be nice to my users but don't want to get malicious code by mistake.
  Looking in SO many questions I decided to go whitelisting, so I get only characters I approve.</p>
  
  <p>How is it possible to be kind to the user, so I let them enter many characters and still keep my inputs safe from malicious code?<br>
  I am using Apache with PHP 5.3.8, I haven't incorporated PDO because the time I heard of it it I was deep into the project and feared it might be too big of a change.</p>
  
  <p>Any ideas would help!</p>