Short & modern
You cancan catch form input values using FormData and send them by fetchfetch
fetch(form.action, {method:'post', body: new FormData(form)}); function send() { let form = document.forms['inputform']; fetch(form.action, {method:'post', body: new FormData(form)}); }<form name="inputform" action="somewhere" method="post"> <input value="person" name="user"> <input type="hidden" value="password" name="pwd"> <input value="place" name="organization"> <input type="hidden" value="key" name="requiredkey"> </form> <!-- I remove type="hidden" for some inputs above only for show them --><br> Look: chrome console>network and click <button onclick="send()">send</button>