Get State From Zip - Pure JS

Gets the US State for a give ZIP. Pure JavaScript implementation.

HTML

ZIP:
<input type='text' id='ZIPCode' value='6822' />
<input type='select' id='selectMe' value='Bitte auswählen...' />
<button id="GetStateButton">Get State</button>
<p></p>State:
<div id='divResult'></div>

JavaScript

var getStatebutton = document.getElementById('GetStateButton');
var myVar, i;

getStatebutton.onclick = function () {
    var zipCode = document.getElementById('ZIPCode');
    var zip = zipCode.value;
    if (!zip) return;
    var url = 'http://api.zippopotam.us/at/' + zip;
    var xhr = new XMLHttpRequest();

    xhr.onreadystatechange = function () {
        if (xhr.readyState == 4) {
            var result = xhr.responseText;
            var zippo = JSON.parse(result);
            var resultDiv = document.getElementById('divResult');
            resultDiv.innerHTML = zippo.places[0].state;
            
           for (i = 0; i < result.length; i++){
            	myVar = zippo.places[i] ;
                selectMe.innerHTML += myVar["place name"] + "<br>";
          
               } 
        	}
    };
    xhr.open('GET', url, true);
    xhr.send(null);
};