Once you've called the GoogleMap function, you can set ID, height, and width of the map (mapcanvas.id, mapcanvas.style.height and mapcanvas.style.width). You can set map default functionality like zoom, position, and control under var myOptions:
var myOptions = {
zoom: 15,
center: latlng,
mapTypeControl: false,
navigationControlOptions: {style: google.maps.NavigationControlStyle.SMALL},
mapTypeId: google.maps.MapTypeId.ROADMAP
};