Java EE (Java Enterprise Edition) General Discussion

Hi ,
I am new to jsp,javascript and i have a little question.
If i make a function in a js file and want to call it from a jsp file without any event ,ie can i write some thing like <%abc()%> in ths jsp page ,which call the function from another .js file.
I suppose that it can be done as gmail page reloads it self after some time and for http mostly we use pull ie request from the client side ,so i think that they must be doing something like timer expiry and reload themselves.

please help me with the solution.
Thanks & Regards
Saurabh