Google Maps API infobox - click one infobox and close the others

by ian_smithz

HTML

<script src="https://maps.googleapis.com/maps/api/js?sensor=false&amp;dummy=.js"></script>
<script src="https://google-maps-utility-library-v3.googlecode.com/svn/trunk/markerclusterer/src/markerclusterer.js"></script>
<script src="https://google-maps-utility-library-v3.googlecode.com/svn/tags/infobox/1.1.9/src/infobox.js"></script>
<div id="map_canvas" class="google-map google-map-full" style="margin-top: 60px;"></div>

CSS

#map_canvas {
    height: 500px;
}

JavaScript

// build portfolios list
var portfolios = [
    ['Title 1', 14.3522, 100.5766, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 2', 17.0077, 99.8230, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 3', 19.3833, -155.2, 'http://imageshack.us/scaled/landing/819/icongreen.png', 'http://www.youtube.com'],
    ['Title 4', 36.0583, -107.9588, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 5', 45.4375, 12.33583, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 6', 39.913908, 116.397196, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 7', 40.649167, 117.4119, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 8', 34.3911, 109.2890, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 9', 40.041452, 94.809282, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 10', 36.1833, 116.8333, 'http://imageshack.us/scaled/landing/153/iconmixed.png', 'http://www.youtube.com'],
    ['Title 11', 39.733, 115.917, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 12', 46.8075, -71.2071, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 13', 34.1236, 35.6511, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 14', 40.6891, -74.0444, 'http://imageshack.us/scaled/landing/849/iconblue.png', 'http://www.youtube.com'],
    ['Title 15', 59.3833, -112.9833, 'http://imageshack.us/scaled/landing/819/icongreen.png', 'http://www.youtube.com'],
    ['Title 16', -13.1630, -72.5455, 'http://imageshack.us/scaled/landing/153/iconmixed.png', 'http://www.youtube.com'],
    ['Title 17', 18.4638, -66.1191,...