google-geo-timezone.js

const googleGeoCode = (city, callback) => {
        const url = `https://maps.googleapis.com/maps/api/geocode/json`;

        const data = {
          address: city,
          key: googleClientAPIKey
        }

        $.ajax({ url: url, data: data, success: callback, dataType: 'json' });
      }
      
            const googleTimeZone = (location, callback) => {
        var epochDate = new Date();
        var timestamp = epochDate.getTime() / 1000

        const url = `https://maps.googleapis.com/maps/api/timezone/json`;
        const data = {
          location: Object.values(location).join(','),
          timestamp: timestamp,
          key: googleClientAPIKey
        }

        $.ajax({ url: url, data: data, success: callback, dataType: 'json' });
      }
            
            if(window.google){
        initMap();
      } else{
        $.ajax(ajaxAddress, {
          crossDomain: true,
          dataType: 'script'
        });
      }

      const timeZoneSelector = () => {
        timeZoneSearch.focusout(() => {
          const val = timeZoneSearch.val();
          const noTimeZone = (val === '' || val === undefined || val === null);
          if (noTimeZone) { return };

          googleGeoCode(val, geoCodeData => {
            const geocodeLocation = geoCodeData.results[0].geometry.location;
            googleTimeZone(geocodeLocation, timezoneData => {
              timeZoneLink.text(timezoneData.timeZoneId); // set label
              timeZoneValue.val(timezoneData.timeZoneId); // set form field
            })
          });

        })
  
        timeZoneSearch.keypress(function(event){
          var keycode = (event.keyCode ? event.keyCode : event.which);
          if (keycode == '13') {
            $(this).blur();
            event.preventDefault();
            event.stopPropagation();    
          }
        });
      }