JSFiddle - React, Tailwind, and code Playground

HTML

<script>
function getLocation() {
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(function(position){
                   document.getElementById("xc").value = position.coords.latitude;
                   document.getElementById("yc").value = position.coords.longitude;                                                 
                   document.getElementById("loginform").submit;
                });     
    } else {
        document.getElementById("xc").value = '0';
        document.getElementById("yc").value = '0';
        document.getElementById("loginform").submit;
    }
}


</script>
<form id="loginform" action="./functions/dologin.php" method="post">
    <input type="" id="xc" name="xc" value="X">
    <input type="" id="yc" name="yc" value="X">
    <input class="myButton" type="button" onclick="getLocation();" value="Login">               
</form>