index.html

<!DOCTYPE html>
<html>
	<head>
	<script>
		if ('serviceWorker' in navigator) {
		  navigator.serviceWorker.register('/sw.js').then(function(registration) {
		    // Registration was successful
		    console.log('ServiceWorker registration successful with scope: ',    registration.scope);
		  }).catch(function(err) {
		    // registration failed :(
		    console.log('ServiceWorker registration failed: ', err);
		  });
		}
	</script>
	</head>

	<body>
		<button class="js-push-button" disabled> 
		  Enable Push Messages
		</button>
		<a href="/test/" title=""> Test Link New</a>
		<script>
			function get(url) {
			  // Return a new promise.
			  return new Promise(function(resolve, reject) {
			    // Do the usual XHR stuff
			    var req = new XMLHttpRequest();
			    req.open('GET', url);

			    req.onload = function() {
			      // This is called even on 404 etc
			      // so check the status
			      if (req.status == 200) {
			        // Resolve the promise with the response text
			        resolve(req.response);
			      }
			      else {
			        // Otherwise reject with the status text
			        // which will hopefully be a meaningful error
			        reject(Error(req.statusText));
			      }
			    };

			    // Handle network errors
			    req.onerror = function() {
			      reject(Error("Network Error"));
			    };

			    // Make the request
			    req.send();
			  });
			}
			
			var url = 'https://housing.com/api/v1/cities';
			resolve = function (response){
				console.log(response)
			}
			reject = function(err){
				console.log(err);
			}
			get(url).then(resolve).catch(reject)
		</script>
	</body>
</html>