From http://www.advancedcustomfields.com/resources/field-types/google-map/

new_gist_file

<style type="text/css">
 
.acf-map {
	width: 100%;
	height: 400px;
	border: #ccc solid 1px;
	margin: 20px 0;
}
 
</style>
<script src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
<script type="text/javascript">
(function($) {
 
/*
*  render_map
*
*  This function will render a Google Map onto the selected jQuery element
*
*  @type	function
*  @date	8/11/2013
*  @since	4.3.0
*
*  @param	$el (jQuery element)
*  @return	n/a
*/
 
function render_map( $el ) {
 
	// var
	var $markers = $el.find('.marker');
 
	// vars
	var args = {
		zoom		: 16,
		center		: new google.maps.LatLng(0, 0),
		mapTypeId	: google.maps.MapTypeId.ROADMAP
	};
 
	// create map	        	
	var map = new google.maps.Map( $el[0], args);
 
	// add a markers reference
	map.markers = [];
 
	// add markers
	$markers.each(function(){
 
    	add_marker( $(this), map );
 
	});
 
	// center map
	center_map( map );
 
}
 
/*
*  add_marker
*
*  This function will add a marker to the selected Google Map
*
*  @type	function
*  @date	8/11/2013
*  @since	4.3.0
*
*  @param	$marker (jQuery element)
*  @param	map (Google Map object)
*  @return	n/a
*/
 
function add_marker( $marker, map ) {
 
	// var
	var latlng = new google.maps.LatLng( $marker.attr('data-lat'), $marker.attr('data-lng') );
 
	// create marker
	var marker = new google.maps.Marker({
		position	: latlng,
		map			: map
	});
 
	// add to array
	map.markers.push( marker );
 
	// if marker contains HTML, add it to an infoWindow
	if( $marker.html() )
	{
		// create info window
		var infowindow = new google.maps.InfoWindow({
			content		: $marker.html()
		});
 
		// show info window when marker is clicked
		google.maps.event.addListener(marker, 'click', function() {
 
			infowindow.open( map, marker );
 
		});
	}
 
}
 
/*
*  center_map
*
*  This function will center the map, showing all markers attached to this map
*
*  @type	function
*  @date	8/11/2013
*  @since	4.3.0
*
*  @param	map (Google Map object)
*  @return	n/a
*/
 
function center_map( map ) {
 
	// vars
	var bounds = new google.maps.LatLngBounds();
 
	// loop through all markers and create bounds
	$.each( map.markers, function( i, marker ){
 
		var latlng = new google.maps.LatLng( marker.position.lat(), marker.position.lng() );
 
		bounds.extend( latlng );
 
	});
 
	// only 1 marker?
	if( map.markers.length == 1 )
	{
		// set center of map
	    map.setCenter( bounds.getCenter() );
	    map.setZoom( 16 );
	}
	else
	{
		// fit to bounds
		map.fitBounds( bounds );
	}
 
}
 
/*
*  document ready
*
*  This function will render each map when the document is ready (page has loaded)
*
*  @type	function
*  @date	8/11/2013
*  @since	5.0.0
*
*  @param	n/a
*  @return	n/a
*/
 
$(document).ready(function(){
 
	$('.acf-map').each(function(){
 
		render_map( $(this) );
 
	});
 
});
 
})(jQuery);
</script>