Moving javascript to external file with body onload dependencies

Hi! I'm trying to move all of my javascript to an external file. I'm new to javascript and don't know how to get the dependent body onload and onunload to work with external .js. Here is where it works with the script in the page:
http://www.fortwayne2030.org/examplegmap3.html
Here is where I'm trying to separate the js:
http://www.fortwayne2030.org/examplegmap.html

Any help would be appreciated!
Thanks!
-TNT