title: Thymeleaf passing fragment parameter to javascript method with th:onclick
body: <p>I'm trying to use th:onclick to call a submit() on form whose ID is given as Thymeleaf variable. I write:</p>
  <pre><code>th:fragment=&quot;fragGname(formname)&quot;
  ......
  th:onclick=&quot;'document.getElementById(\''  + ${formname} +  '\').submit();'&quot;&gt;
  </code></pre>
  <p>But I receive the error</p>
  <blockquote>
  <p>org.thymeleaf.exceptions.TemplateProcessingException: Only variable expressions returning numbers or booleans are allowed in this context, any other datatypes are not trusted in the context of this expression, including Strings or any other object that could be rendered as a text literal. A typical case is HTML attributes for event handlers (e.g. &quot;onload&quot;), in which textual data from variables should better be output to &quot;data-*&quot; attributes and then read from the event handler.</p>
  </blockquote>
  <p>Where is the mistake? Thanks!</p>