[OpenLayers-Dev] Vector layer fails, if constructed before the page has finished loading

Mon Mar 19 16:38:45 EDT 2007

OK - further info.

You can't declare a vector layer in inline javascript, you have to
declare it in a function that's called by a client-side event.

The vectorfeatures example declares a vector layer in an init()
function, and init() is called on the onload event of <body>.  This
worked.

My ASPX conversion called init() in an emitted Javascript block, placed
near the end of the file
by ClientScript.RegisterStartupScript().  This did not work.

What works:

   <html>
   <head runat="server">
      <title>Untitled Page</title>
      <script type="text/javascript"
src="openlayers/lib/OpenLayers.js"></script>
      <script type="text/javascript">
         <!--
         var map;
         function init(){
            map = new OpenLayers.Map( $('map') );
            var vectorLayer = new OpenLayers.Layer.Vector("Simple
Geometry");
		[...]
         }
         // -->
      </script>
   </head>
   <body onload="init();">
      <form id="form1" runat="server">
      <div id="map"></div>
      </form>
   </body>
   </html>

What doesn't work:

   <html>
   <head runat="server">
      <title>Untitled Page</title>
      <script type="text/javascript"
src="openlayers/lib/OpenLayers.js"></script>
      <script type="text/javascript">
         <!--
         var map;
         function init(){
            map = new OpenLayers.Map( $('map') );
            var vectorLayer = new OpenLayers.Layer.Vector("Simple
Geometry");
		[...]
         }
         // -->
      </script>
   </head>
   <body>
      <form id="form1" runat="server">
      <div id="map"></div>
         <script type="text/javascript" defer="defer">
         init();
         </script>
      </form>
   </body>
   </html>

The vector layer constructor fails, if it's called before the page has
entirely loaded.

None of the other layers I've worked with have this dependency.