[Deff]

<div id="filt_city" style="display:none">Привет Пермякам!</div>
<script>function showCity(o){
    var regionName = o.regionName
    alert(regionName);
    var testRegion = "Perm Krai";
    var isTest = (testRegion == regionName);
    if(isTest)document.getElementById('filt_city').style.display='block';
}</script>
<script src="http://ip-api.com/json/?fields=country,city,regionName&callback=showCity"></script>