google-forms.html

<script type="text/javascript">var submitted=false;</script>
<iframe name="hidden_iframe"
    id="hidden_iframe"
    style="display:none;" 
    onload="if(submitted) {window.location='http://domain.com/thanks.html';}">
</iframe>
<form action="https://docs.google.com/forms/d/cdjhesjd2763jhdjsshdjdshdjs267263723jhj23hjc/formResponse" 
    method="post"
    target="hidden_iframe"
    onsubmit="submitted=true;">
        <input type="email" name="entry_1234554563" placeholder="Your Email" required>
        <input type="hidden" name="draftResponse" value="[,,&quot;5989133595295011097&quot;]">
        <input type="hidden" name="pageHistory" value="0">
        <input type="hidden" name="fbzx" value="2468264382463823677">
        <input type="submit" name="submit" id="someid" class="someclass">
</form>