Calculate distance using google api from searching zip code

I got a list if addresses showed in a list and one search filter containing textbox to insert Zip code.
Now I need to calculate the distance between the filtering Zip code and each address showing in the list. To do this I used google api.
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jQuery(document).ready(function () {
  if(jQuery('.atm-zip').children().val().length>0)
  {
   //get the filtering zip value and calculate the distance
    getLatLngFromAddress(jQuery('.atm-zip').children().val()); 
  }
});

var geocoder;
//filtering zip's lat
var p1lt;
//filtering zip's long
var p1ln;

function getLatLngFromAddress(postal_code) {
   if (geocoder == null) {
        geocoder = new google.maps.Geocoder();
    }
    var searchLoc;
    geocoder.geocode({ 'address': postal_code }, function (results, status) {
        if (status == google.maps.GeocoderStatus.OK) {
            searchLoc = results[0].geometry.location;
            p1lt=searchLoc.lat();
            p1ln=searchLoc.lng();
        }
          jQuery('.atm_list li').each(function(){
            //listed address's lat
            var p2lt=jQuery(this).find('.GeoLat').text();
            //listed address's long
            var p2ln=jQuery(this).find('.GeoLong').text();
           
            jQuery(this).find('.GeoDistance').text(getDistance(p2lt,p2ln) +' mi');                     
          });       
    });
}

var rad = function(x) {
  return x * Math.PI / 180;
};







//this is a function to calculate distance between 2 geographic points
function getDistance(p2lt,p2ln) {
          var R = 6378137; // Earth’s mean radius in meter
          var dLat = rad(p2lt - p1lt);
          var dLong = rad(p2ln - p1ln);
          var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
          Math.cos(rad(p1lt)) * Math.cos(rad(p2lt)) *
          Math.sin(dLong / 2) * Math.sin(dLong / 2);
          var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
          var d = R * c;
          var resultInMile=d*0.000621371;
          var finalResult=parseFloat(Math.round(resultInMile * 100) / 100).toFixed(2);
          return finalResult; // returns the distance in meter then converted to miles
      }