if you doubt JSP then dont worry its an excellent technology.
If you have a question about javascript you are in the wrong forum but seeing your question ill first answer this:
javascript = CLIENT side
jsp/struts = SERVER side
in no way can both access/use/assign each other.
You can have your JSP/stutrs render HTML that includes Javascript with the needed values. and then have your JAvascript make a request to your webserver so JSP/Struts can do something with it.
example:
<script type="text/javascript">
var ajavascriptvar = <c:out value=${yourstrutsform.yourproperty} />;
</script>
Yes you can use javascript to access form values. I'm using this method to do client side validation before sending the values to the server.
The form name is the name of the form you gave in the struts-config. Form object name is the same as like what you give using the struts tags. Accessing the attributes of each object is just the same as you would do using javascript. You can retrieve value, set value, etc.
Somemore, you can even use attributes like onclick, onsubmit, etc in your Struts tags.