Leaflet remove marker

<!DOCTYPE html>
<html>
  <head>
    <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.css"  data-require="leaflet@0.7.3" data-semver="0.7.3" />
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <div id="map"></div>
    <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.js" data-require="leaflet@0.7.3" data-semver="0.7.3"></script>
    <script type="text/javascript" src="script.js"></script>
  </body>
</html>

var map = L.map('map', {
  'center': [0, 0],
  'zoom': 1,
  'layers': [
    L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
      'attribution': 'Map data &copy; OpenStreetMap contributors'
    })
  ]
});

var marker = L.marker([0, 0]).addTo(map);

map.on('click', function () {
  map.removeLayer(marker);
});

body {
  margin: 0;
}
html, body, #map {
  height: 100%;
}