title: How to save PHP code written in Wordpress page
body: <p>I'm using Artisteer to create WordPress themes.
  Artisteer is not able to include php code into pages, then I have to do some modification via WordPress page editor.</p>
  
  <p>I'm using "PHP Insert" plugin to include php code into WordPress page editor and to make WordPress able to use my php code into my pages.</p>
  
  <p>In my site I have a form for B.M.I. calculation and I need to use php code in the page.</p>
  
  <p>The problem is that if I change the theme in Artisteer and if I upload it into WordPress, I loose php changes.
  It's very boring to apply modification every time (and also dangerous...lost code, wrong code position,...).</p>
  
  <p>I'm thinking to use a child theme, but I don't know how to apply it to php code added into pages.</p>
  
  <p>Suggestions?</p>
  
  <p>Thanks in advance</p>