title: Uncaught TypeError: document.getElementById(...).value.trigger is not a function
body: <p>I have written a function to display selected form items on the console and trigger whenever user changes his/her selection.</p>
  
  <p>I am getting below error in it,</p>
  
  <pre><code>options-general.php?page=my-unique-identifier:397 Uncaught TypeError: document.getElementById(...).value.trigger is not a function
  </code></pre>
  
  <p>Here is my code,</p>
  
  <pre><code>function my_plugin_options() {
      if ( !current_user_can( 'manage_options' ) )  {
          wp_die( __( 'You do not have sufficient permissions to access this page.' ) );
      }
      echo '&lt;div class="wrap"&gt;';
      echo '      &lt;h3&gt;Form:&lt;/h3&gt;
                  &lt;form&gt;
                      Provide PDF Link:&lt;br&gt;
                      &lt;input type="url" id="url" name="url" placeholder="http://"&gt;
                      &lt;br&gt;&lt;br&gt;
                      Select Flipbook Theme:&lt;br&gt;
                      &lt;input type="radio" id="theme" name="theme" value="bible" checked&gt; Bible&lt;br&gt;
                      &lt;input type="radio" id="theme" name="theme" value="magazine"&gt; Magazine&lt;br&gt;
                      &lt;input type="radio" id="theme" name="theme" value="magazine single"&gt; Magazine Single&lt;br&gt;&lt;br&gt;
                      &lt;button type="button"&gt;Get Code&lt;/button&gt;&lt;br&gt; 
                  &lt;/form&gt;
                      &lt;div id="code" style="background-color:green;"&gt;
                      &lt;/div&gt;
                      &lt;div id="preview"&gt;
                      &lt;h3&gt;Preview:&lt;/h3&gt;
                      &lt;/div&gt;
                  &lt;script&gt;    
                      jQuery(document).ready(function($){
                          var url = document.getElementById("url").value.trigger("change");
                          var theme = document.getElementById("theme").value.trigger("change");
                          console.log(theme);
                      }); 
                  &lt;/script&gt;
          ';
      echo '&lt;/div&gt;';
  }
  </code></pre>