Change Dropdown

I have this code but it's not working because the current_language variable only updates upon page load and the gTranslate options do not reload the page

<input type="button" id="YourButtonES" value="Español" />
<input type="button" id="YourButtonEN" value="Inglés" />
 
<script>

buttonES = document.getElementById("YourButtonES");
buttonEN = document.getElementById("YourButtonEN");
buttonES.style.visibility = 'visible';
buttonEN.style.visibility = 'hidden';

var current_language = gt_get_cookie('googtrans').split('/').pop();
console.log("current lang " + current_language);

if (current_language === 'es') {
    buttonES.style.visibility = 'hidden';
    buttonEN.style.visibility = 'visible';
} else {
    buttonES.style.visibility = 'visible';
    buttonEN.style.visibility = 'hidden';
}

//GTranslate code
function gt_get_cookie(cname) {
    var name = cname + "=";
    var decodedCookie = decodeURIComponent(document.cookie);
    var ca = decodedCookie.split(';');
   
    for(var i = 0; i <ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') {
            c = c.substring(1);
        }
        
        if (c.indexOf(name) == 0) {
            console.log(name.length);
            return c.substring(name.length, c.length);
        }
    }
    console.log('return');
    return "";
}
</script>