title: Using variable inside a function
body: <p>This seems like a really simple issue, but I'm not having any luck solving it and not entirely sure what to search. I am trying to get $logo to be used by the funciton, so that the image uses the variable defined on line 1:</p>
  
  <pre><code>$logo = 'http://dev.batman.com/logo.png';
  
  function signup_email_body( $logo ){
    $body = '&lt;img src="'.$logo.'" /&gt;';
  }
  </code></pre>
  
  <p>The funciton is then triggered on signup and the src attribute is missing.</p>
  
  <p>(n.b. the above is simplified code to save masses of HTML)</p>