您需要根据地理编码操作的结果设置标记的位置。

  $（＃location）。change（function（）{
 var addr =（$（'＃location'）。val（））; 
 $ b $ var geocoder = new google.maps.Geocoder（）; 
 geocoder.geocode（{'address'：addr 
}，function（results，status）{
（if status == google.maps.GeocoderStatus.OK）{
 map.setCenter（results [0] .geometry.location）; 
 geoMarker.setPosition（results [0] .geometry.location） ; 
} else {
 alert（Something wrong wrong+ status）; 
} 
}）; 
}）; 
 

概念证明小提琴

程式码片段：

  var geocoder; var map; var geoMarker;函数initialize（）{var map = new google.maps.Map（document.getElementById（map_canvas），{center：new google.maps。 LatLng（37.4419，-122.1419），zoom：13，mapTypeId：google.maps.MapTypeId.ROADMAP}）; geoMarker = new google.maps.Marker（）; geoMarker.setPosition（map.getCenter（））; geoMarker.setMap（地图）; $（＃location）。change（function（）{var addr =（$（'＃location'）。val（））; var geocoder = new google.maps.Geocoder（）; geocoder.geocode（{'address '：addr}，function（results，status）{if（status == google.maps.GeocoderStatus.OK）{map.setCenter（results [0] .geometry.location）; geoMarker.setPosition（results [0] .geometry .location）;} else {alert（Something got wrong+ status）;}}）;}）;} google.maps.event.addDomListener（window，load，initialize）;   html，body，＃map_canvas {height：100％;宽度：100％; margin：0px; < script src =https：//  / ajax / js>< / script>< select id =location> &LT;选项&GT;迪拜&LT; /选项&GT; < / option> Sharjah< / option>< / select>< div id =map_canvas>< / div> 

I want to change map marker position on basis of dropdown change even,What I'm doing is I get lat,long on dropdown event and want to pass these coordinates to my current marker , this is my code

$("#location").change(function () {
    var addr = ($('#location').val());

    var geocoder = new google.maps.Geocoder();
    geocoder.geocode({ 'address': addr }, function (results, status) {
        if (status == google.maps.GeocoderStatus.OK) {
            alert("location : " + results[0].geometry.location.lat() + " " + results[0].geometry.location.lng());
            geoMarker.setMarkerOptions({
                duration: duration,
                easing: $('#easingOption').val()
            });
        } else {
            alert("Something got wrong " + status);
        }
    });
});

HTML :

<select id="location">
    <option>Dubai</option>
    <option>Sharjah</option>
</select>

It alerts current coordinates but I need to know how do I pass these coordinates to my marker position

You need to set the position of the marker based on the results of the geocode operation.

$("#location").change(function() {
  var addr = ($('#location').val());

  var geocoder = new google.maps.Geocoder();
  geocoder.geocode({'address': addr
  }, function(results, status) {
    if (status == google.maps.GeocoderStatus.OK) {
      map.setCenter(results[0].geometry.location);
      geoMarker.setPosition(results[0].geometry.location);
    } else {
      alert("Something got wrong " + status);
    }
  });
});

proof of concept fiddle

code snippet:

var geocoder;
var map;
var geoMarker;

function initialize() {
  var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, -122.1419),
      zoom: 13,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  geoMarker = new google.maps.Marker();
  geoMarker.setPosition(map.getCenter());
  geoMarker.setMap(map);

  $("#location").change(function() {
    var addr = ($('#location').val());

    var geocoder = new google.maps.Geocoder();
    geocoder.geocode({
      'address': addr
    }, function(results, status) {
      if (status == google.maps.GeocoderStatus.OK) {
        map.setCenter(results[0].geometry.location);
        geoMarker.setPosition(results[0].geometry.location);
      } else {
        alert("Something got wrong " + status);
      }
    });
  });

}
google.maps.event.addDomListener(window, "load", initialize);

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js"></script>
<select id="location">
  <option>Dubai</option>
  <option>Sharjah</option>
</select>
<div id="map_canvas"></div>