As @PirateApp mentioned in his comment, it's explicitly against Google's Maps API Licensing to use the Maps API as you intend.
You have a number of alternatives, including downloading a Geoip database and querying it locally or using a third party API service, such as my service ipdata.co.
ipdata gives you the geolocation, organisation, currency, timezone, calling code, flag and Tor Exit Node status data from any IPv4 or IPv6 address.
And is scalable with 10 global endpoints each able to handle >10,000 requests per second!
This answer uses a 'test' API Key that is very limited and only meant for testing a few calls. Signup for your own Free API Key and get up to 1500 requests daily for development.
$.get("https://api.ipdata.co?api-key=test", function(response) {_x000D_
$("#ip").html("IP: " + response.ip);_x000D_
$("#city").html(response.city + ", " + response.region);_x000D_
$("#response").html(JSON.stringify(response, null, 4));_x000D_
}, "jsonp");
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<h1><a href="https://ipdata.co">ipdata.co</a> - IP geolocation API</h1>_x000D_
_x000D_
<div id="ip"></div>_x000D_
<div id="city"></div>_x000D_
<pre id="response"></pre>
_x000D_
The fiddle; https://jsfiddle.net/ipdata/6wtf0q4g/922/