html - GMaps API v3 loading, but can't view it on page -

i know maps loading, whatever reason can't see them.

js

function initialize() {   var mylatlng = new google.maps.latlng(-25.363882,131.044922);   var mapoptions = {     zoom: 4,     center: mylatlng,     maptypeid: google.maps.maptypeid.roadmap   }   var map = new google.maps.map(document.getelementbyid('map-canvas'), mapoptions);    var marker = new google.maps.marker({       position: mylatlng,       map: map,       title: 'hello world!'   }); } 

markup

<div id="map-canvas">  </div> 

i know must simple , i'm little confused why can't work out, here link: http://stage.sexdiaries.co.uk/map

you need give map size:

<div id="map-canvas" style="height:500px;width:600px;"></div>