[javascript] Google Map API v3 ~ Simply Close an infowindow?

Or you can share/reuse the same infoWindow object. See this google demo for reference.

Same code from demo

var Demo = { map: null,  infoWindow: null
};

/**
 * Called when clicking anywhere on the map and closes the info window.
 */
Demo.closeInfoWindow = function() {
  Demo.infoWindow.close();
};

/**
 * Opens the shared info window, anchors it to the specified marker, and
 * displays the marker's position as its content.
 */
Demo.openInfoWindow = function(marker) {
  var markerLatLng = marker.getPosition();
  Demo.infoWindow.setContent([
    '<b>Marker position is:</b><br/>',
    markerLatLng.lat(),
    ', ',
    markerLatLng.lng()
  ].join(''));
  Demo.infoWindow.open(Demo.map, marker);
},

/**
 * Called only once on initial page load to initialize the map.
 */
Demo.init = function() {
  // Create single instance of a Google Map.
  var centerLatLng = new google.maps.LatLng(37.789879, -122.390442);
  Demo.map = new google.maps.Map(document.getElementById('map-canvas'), {
    zoom: 13,
    center: centerLatLng,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  });

  // Create a single instance of the InfoWindow object which will be shared
  // by all Map objects to display information to the user.
  Demo.infoWindow = new google.maps.InfoWindow();

  // Make the info window close when clicking anywhere on the map.
  google.maps.event.addListener(Demo.map, 'click', Demo.closeInfoWindow);

  // Add multiple markers in a few random locations around San Francisco.
  // First random marker
  var marker1 = new google.maps.Marker({
    map: Demo.map,
    position: centerLatLng
  });

  // Register event listeners to each marker to open a shared info
  // window displaying the marker's position when clicked or dragged.
  google.maps.event.addListener(marker1, 'click', function() {
    Demo.openInfoWindow(marker1);
  });

  // Second random marker
  var marker2 = new google.maps.Marker({
    map: Demo.map,
    position: new google.maps.LatLng(37.787814,-122.40764),
    draggable: true
  });

  // Register event listeners to each marker to open a shared info
  // window displaying the marker's position when clicked or dragged.
  google.maps.event.addListener(marker2, 'click', function() {
    Demo.openInfoWindow(marker2);
  });

  // Third random marker
  var marker3 = new google.maps.Marker({
    map: Demo.map,
    position: new google.maps.LatLng(37.767568,-122.391665),
    draggable: true
  });

  // Register event listeners to each marker to open a shared info
  // window displaying the marker's position when clicked or dragged.
  google.maps.event.addListener(marker3, 'click', function() {
    Demo.openInfoWindow(marker3);
  });
}