title: how to create a plain html form in yii2?
body: <p>I tried e.g</p>
  
  <pre><code>&lt;form id='blah' action='myActionController' method='post'&gt;
  //fields here
  &lt;input type='submit' name='submit' value='button name' /&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>after clicking the button, it does land to the <code>www.mydomain.com/site/myActionController</code></p>
  
  <p>but then, the page content is </p>
  
  <pre><code>Bad Request (#400)
  Unable to verify your data submission. 
   The above error occurred while the Web server was processing your request.
  
  Please contact us if you think this is a server error. Thank you. 
  </code></pre>
  
  <p>I just don't want to use the active form...
  so how to do the form in a plain html version without using the built-in yii
  active form?</p>