how to stop google map zoom to not refresh when return to map

[Lisa23]

Hi i have this google map on the page which the user can zoom for a location then click on the location link and will open a new page, what i am trying to do is on that new page theres a back to map button which returns to the map using (href='javascript:history.go(-1)'>) now that returns to the page fine the problem is that it when go back to the map it seem to unzoom is there a way i could return to the page without refreshing the page this way hopefully the zoom will be on the same location. i tried had this code on the map page but didnt work

 

<script type="text/javascript">
function refresh()
{
    window.location.reload(false);
}
</script>

 

this my page

http://www.estateagentsonfilm.co.uk/area_films.php if you click one of the maps it will open a view film link click on that will open new page i want to be able to return to the map page keep the zoom in if you zoom

 

is that possible if so help

 

please thanks