Javascript function call from vb.net

Hello,
I am new to asp pages and need some further assistance. Now I have the map which is loaded by a function (function GetMap()
{
var latLon = new VELatLong(txtLat.value, txtLong.value);
map = new VEMap('myMap');
map.LoadMap(latLon, zoom, selStyle );
} ) on the page
I want to be able to load and hide the map until an item is selected on a gridview, what code would I need to place
in the GridView1_SelectedIndexChanged to triger to call an asp page function getmap, using vb.net?
Regards,
Joe

Use CSS to hide the map by default, and then when an item is selected have a javascript fire to change the visibility from hidden to visible

Hi Mike,
Thanks for the quick response, I am unsure of the syntax to make the call from the event. Have you an example?
Regards,
Joe