Google Map will not display in ASP.NET Master Page - asp.net

Question

I am trying to display a simple map in an ASP.NET page that has a Master Page. Everything works fine when I put the code in a static HTML page but nothing displays when using asp.net not even an error. When comparing the request/response in fiddler I can see that google is not sending any images back when using asp.net master page.
Here's my client side code (I can hit a break point here):
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<style type="text/css">
html { height: 100% }
body { height: 100%; margin: 0; padding: 0 }
#map_canvas { height: 100%; background-color:#eeeeee;}
</style>
<script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=false"></script>
<script type="text/javascript">
function initialize() {
var latlng = new google.maps.LatLng(-34.397, 150.644);
var myOptions = {
zoom: 8,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var mapDiv = document.getElementById("map_canvas");
var map = new google.maps.Map(mapDiv, myOptions);
}
</script>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server">
<div id="map_canvas" style="width:100%; height:100%"></div>
</asp:Content>
I call the script from the server:
Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
Dim mybodytag As HtmlGenericControl
mybodytag = Page.Master.FindControl("mainbody")
mybodytag.Attributes.Add("onload", "initialize()")
End Sub

Answer 1

Found the solution. I changed the div % to a fixed px size and it worked:
<div id="map_canvas" style="width:800px; height:600px"></div>