Dropdown – Redirect depending on choice

Hello! I would like to have a different redirect depending on the choice chosen in the dropdown field. I found this code, but it redirects as soon you select it. I would like the send button to do the redirect instead. So you chose, then click button to start.

select id=”selectbox” name=”” onchange=”javascript:location.href = this.value;”>
<option value=”https://www.yahoo.com/&#8221; selected>Option1</option>
<option value=”https://www.google.co.in/”>Option2</option&gt;
<option value=”https://www.gmail.com/”>Option3</option&gt;

</select>

[submit “Démarrer”]

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