title: HtmlService form submit opens new tab with foo bar URL
body: <p>I am attempting to build a UI for a spreadsheet using GAS HtmlService. The HTML below is a very simple form with a single text box that pulls a value ("Kristina") from the sheet, successfully. However, when I try to submit the form a new tab is opened in Chrome that attempts to open the URL "bffc95ee-ff64-4d2c-xxxx-19d9824eb4b4.foo.bar/?fname=Kristina" with "xxxx" replacing more random letters and numbers (just in case). At no point do I use the words "foo.bar" in my code, so I'm pretty sure that that part isn't coming from me. It does not change each time or after logging out and back in. I'm getting the same result on two different computers.</p>
  
  <pre><code>&lt;html&gt;
  &lt;body&gt;
    &lt;div&gt;
      &lt;form id="formtest1"&gt;
        &lt;label&gt;First Name&lt;/label&gt;
        &lt;input name="fname" type="text" maxlength="255" value="&lt;?= fname ?&gt;"/&gt;
        &lt;input type="submit" value="Submit" 
            onclick="google.script.run.processForm(document.getElementById('formtest1'));
            google.script.host.close()"/&gt;
      &lt;/form&gt;
    &lt;/div&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>The above is being displayed using the following function:</p>
  
  <pre><code>function htmltest(){
    var ss = SpreadsheetApp.getActiveSpreadsheet();
    var sht = ss.getActiveSheet();
    var html = HtmlService.createTemplateFromFile("HTML");
    html.fname = sht.getRange(2, 3).getValue();
    ss.show(html.evaluate());
  };
  </code></pre>
  
  <p>If I understand correctly, the "google.script.run.processForm(...)" script in the HTML should trigger the following function, as set up in the projects triggers:</p>
  
  <pre><code>function onFormSubmit(){
  Browser.msgBox("Test");
  };
  </code></pre>
  
  <p>But it doesn't appear to do so as the form doesn't close and the msgBox doesn't appear. Only the foo bar URL in a new tab.</p>
  
  <p>Hopefully I've explained the issue clearly and am not making an embarrassing mistake.</p>