title: from google script to html
body: <p>I have a function in a .gs file:</p>
  
  <pre><code>function testReturn(){
   return "Finaly it works!";
  }
  </code></pre>
  
  <p>and an other in an html file:</p>
  
  <pre><code>&lt;script&gt;
    window.addEventListener('load', function() {
      google.script.run.withSuccessHandler(createPost).testReturn();
    });
  
    /**/
  
    document.getElementById("go_button").addEventListener("click",functionGo);
  
    function functionGo(){
  
      var textToDisplay = google.script.run.testReturn();
  
      document.getElementById("input1_id").value = textToDisplay;   
    }
  
  &lt;/script&gt;
  </code></pre>
  
  <p>The return is always "undifined". How can I interact between gs and html script? (Of course I don't only want to return an integer, the project is to get a long text wrote with many functions, I'm just looking for a way to get the result and to dispaly it on a html).</p>
  
  <p>Thanks you</p>