title: Apps script - get sidebar information
body: <p>For some reason I don't get a value from my dropdown in the sidebar to my script as a var. Later on I run different function based on the input. </p>
  
  <p>I followed multiple tutorials, so I don't get it. The log is empty!</p>
  
  <p><strong>HTML script</strong></p>
  
  <pre><code>&lt;div&gt;
    &lt;h4&gt;Here you can filter the projects&lt;/h4&gt;
      &lt;div class="form-group"&gt;
      &lt;label for="projectFilter"&gt;Filter&lt;/label&gt;
      &lt;select class="form-control" id="projectFilter"&gt;
        &lt;option&gt;1&lt;/option&gt;
        &lt;option&gt;2&lt;/option&gt;
        &lt;option&gt;3&lt;/option&gt;
        &lt;option&gt;4&lt;/option&gt;
        &lt;option&gt;5&lt;/option&gt;
      &lt;/select&gt;
    &lt;/div&gt;
    &lt;button id ="runButton" class="btn btn-primary" onClick="pushValue()"&gt;Run&lt;/button&gt;
  &lt;/div&gt;
  
  &lt;script&gt;
  
       function pushValue(){
       var keuze = document.getElementById("projectFilter").value;
       };
  
       google.script.run.pushValue(keuze);
  
  
  &lt;/script&gt;
  </code></pre>
  
  <p><strong>Script</strong></p>
  
  <pre><code>function projectForm(){
  
    const htmlForSidebar = HtmlService.createTemplateFromFile("projectForm");
    const htmlOutput = htmlForSidebar.evaluate();
    htmlOutput.setTitle("CampSolutions");
  
    const ui = SpreadsheetApp.getUi();
    ui.showSidebar(htmlOutput);
  
  }
  
  function pushValue(data){
   var keuze = data;
   Logger.log(keuze);
  }
  </code></pre>
  
  <p><strong>UPDATED script</strong></p>
  
  <pre><code>&lt;script&gt;
       function pushValue(){
       var keuze = document.getElementById("projectFilter").value;
       google.script.run.pushValue(keuze);
       console.log(keuze);
       Logger.log(keuze);
       }
  &lt;/script&gt;
  </code></pre>