title: Calling JS file in PHP
body: <p>Hi Im trying to call a external JavaScript file called <code>ts.js</code> as follows.
  Can some one tell me whether the following approach is right or wrong and reasons for your recommendation.</p>
  
  <p>Thanks you</p>
  
  <pre><code>$variable .= '&lt;input type="submit" name="send" id="send" value="Save" onclick="ts.js" /&gt;';
  </code></pre>